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19-4995; Rev 1; 3/10
TION KIT EVALUA BLE AVAILA
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring
General Description
The MAX8934_ dual-input Li+/Li-Poly linear battery chargers with Smart Power SelectorK safely charge a single Li+/Li-Poly cell in accordance with JEITA recommendations. The MAX8934_ monitors the battery temperature (TBATT) while charging, and automatically adjusts the fast-charge current and charge termination voltage as the battery temperature varies. The MAX8934_ also monitors the battery temperature while the battery is discharging, and provides a warning flag (OT) to the system in the event that the battery is over temperature. Two safety profiles are supported (see Figure 6 for details). An ultra-low IQ, always-on LDO provides an additional 3.3V supply for system power. The MAX8934_ operates with either separate inputs for USB* and AC adapter power, or from a single input that accepts both. All power switches for charging and switching the load between battery and external power are included on-chip. No external MOSFETs are required. The MAX8934_ features a Smart Power Selector to make the best use of limited USB or adapter power. Input current limit and battery charge current limit are independently set. Input power not used by the system charges the battery. Charge current limit and DC current limit can be set up to 1.5A and 2A, respectively, while USB input current can be set to 100mA or 500mA for the MAX8934A/ MAX8934B/MAX8934C/MAX8934E and up to 1.5A (max) for the MAX8934D. Automatic input selection switches the system load from battery to external power. The MAX8934A provides a SYS output voltage of 5.3V, while the MAX8934B-MAX8934E provides a SYS output voltage of 4.35V. Other features include overvoltage protection (OVP), open-drain charge status and fault outputs, power-OK monitors, charge timers, and a battery thermistor monitor. Additionally, on-chip thermal limiting reduces the battery charge-rate to prevent charger overheating. The MAX8934_ is available in a 28-pin, 4mm x 4mm, TQFN package.
Features
S Li+ Charger with Smart Power Selector, No External MOSFETs Needed S Monitors Battery Temperature and Adjusts Charge Current and Termination Voltage Automatically per JEITA Recommendations S OT Flags System of a Hot Battery During Discharge S Ultra-Low IQ, Always-On 3.3V LDO S Common or Separate USB and Adapter Inputs S Automatic Adapter/USB/Battery Switchover S Load Peaks in Excess of Adapter Rating are Supported by Battery S Input OVP to 16V (DC) and 9V (USB) S 40mI SYS-to-BATT Switch S Thermal Regulation Prevents Overheating S 4.35V or 5.3V SYS Regulation Voltage S 1.5A (max) USB Input Current Limit (MAX8934D)
MAX8934A-MAX8934E
Ordering Information
PART TEMP RANGE PIN-PACKAGE MAX8934AETI+ -40NC to +85NC 28 Thin QFN-EP* +Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad.
Ordering Information continued and Selector Guide appears at end of data sheet.
Typical Operating Circuit
LDO 3.3V ALWAYS-ON LINEAR REGULATOR AC ADAPTER DC Q1 CHARGE CURRENT Q3 CHARGE AND SYS LOAD SWITCH SYS LOAD CURRENT SYSTEM LOAD
Applications
PDAs, Palmtop, and Wireless Handhelds Portable Media, MP3 Players, and PNDs Digital Still Cameras and Digital Video Cameras Handheld Game Systems
*Protected by U.S.Patent #6,507,172. Smart Power Selector is a trademark of Maxim Integrated Products, Inc.
USB USB Q2
BATT
BATTERY
GND
MAX8934A- MAX8934E
_______________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring MAX8934A-MAX8934E
ABSOLUTE MAXIMUM RATINGS
DC, PEN1 to GND .................................................-0.3V to +16V USB to GND ............................................................-0.3V to +9V VL to GND ...............................................................-0.3V to +4V LDO to GND ......... -0.3V to the lower of +4V and (VSYS + 0.3V) THMEN, THMSW to GND ..................... -0.3V to +(VLDO + 0.3V) THM to GND .......................................-0.3V to (VTHMSW + 0.3V) PSET, ISET, CT to GND............................... -0.3V to (VL + 0.3V) BATT, SYS, CEN, CHG, OT, DOK, UOK, FLT, DONE, USUS, PEN2 to GND.............-0.3V to +6V EP (Exposed Pad) to GND ...................................-0.3V to +0.3V DC Continuous Current (total in two pins) .................... 2.4ARMS SYS Continuous Current (total in two pins) ................... 2.4ARMS USB Continuous Current (total in two pins) .................. 2.0ARMS BATT Continuous Current (total in two pins)................. 2.4ARMS LDO Continuous Current ............................................. 50mARMS LDO Short-Circuit Duration ......................................... Continuous Continuous Power Dissipation (TA = +70NC) Single-Layer Board (derate 20.8mW/NC above +70NC) ......................1666.7mW Multilayer Board (derate 28.6mW/NC above +70NC) ......................2285.7mW Operating Temperature Range .......................... -40NC to +85NC Junction Temperature ...................................... -40NC to +125NC Storage Temperature ....................................... -65NC to +150NC Lead Temperature (soldering, 10s) ................................+300NC Soldering Temperature (reflow) ......................................+260NC
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VDC = VPEN1 = VPEN2 = 5V, CEN = USUS = THMEN = GND, VBATT = 4V, VTHM = 1.65V, USB, THMSW, CHG, DONE, OT, DOK, UOK, FLT are unconnected, CCT = 0.068FF, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.) (Note 1) PARAMETER DC-to-SYS PREREGULATOR DC Operating Voltage Range DC Withstand Voltage DC Undervoltage Threshold DC Overvoltage Threshold DC Operating Supply Current DC Suspend Current DC-to-SYS On-Resistance DC to BATT Dropout Voltage VBATT = VSYS = 0V When V DOK goes low, VDC rising, 500mV hysteresis When V DOK goes high, VDC rising, 360mV hysteresis ISYS = IBATT = 0mA, V CEN = 0V ISYS = IBATT = 0mA, V CEN = 5V VDC = V CEN = VUSUS = 5V, VPEN1 = 0V ISYS = 400mA, V CEN = 5V When SYS regulation and charging stops, VDC falling, 150mV hysteresis VDC = 6V, VSYS = 5V, TA = +25NC (MAX8934A); VDC = 5V, VSYS = 4V, TA = +25NC (MAX8934B- MAX8934E) RPSET = 1.5kI RPSET = 3kI RPSET = 6.3kI VPEN1 = 0V, VPEN2 = 5V (500mA USB mode) VPEN1 = VPEN2 = 0V (100mA USB mode) MAX8934A MAX8934B-MAX8934E 10 1800 900 450 450 80 1.5 VDC = 6V, ISYS = 1mA to 1.75A, V CEN = 5V 5.2 4.29 5.3 4.35 1.5 50 100 3.95 6.8 4.0 6.9 1 0.8 195 0.2 50 2000 1000 475 475 95 4.1 6.6 14 4.05 7.0 2 1.5 340 0.35 90 2200 1100 500 500 100 6.3 5.4 4.4 kI V ms Fs NC mA V V V V mA FA I mV CONDITIONS MIN TYP MAX UNITS
DC Current Limit
PSET Resistance Range SYS Regulation Voltage Input Current Soft-Start Time Thermal-Limit Temperature
Connecting DC with USB not present Connecting DC with USB present Die temperature at when the charging current and input current limits are reduced
2
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Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring
ELECTRICAL CHARACTERISTICS (continued)
(VDC = VPEN1 = VPEN2 = 5V, CEN = USUS = THMEN = GND, VBATT = 4V, VTHM = 1.65V, USB, THMSW, CHG, DONE, OT, DOK, UOK, FLT are unconnected, CCT = 0.068FF, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.) (Note 1) PARAMETER Thermal-Limit Gain VL Voltage USB-TO-SYS PREREGULATOR USB Operating Voltage Range USB Withstand Voltage USB Undervoltage Threshold USB Overvoltage Threshold USB Operating Supply Current USB Suspend Current USB to SYS On-Resistance USB-to-BATT Dropout Voltage USB Current Limit (See Tables 2a and 2b for Input Source Control) VBATT = VSYS = 0V When V UOK goes low, VUSB rising, 500mV hysteresis When V UOK goes high, VUSB rising, 360mV hysteresis ISYS = IBATT = 0mA, V CEN = VPEN2 = 0V ISYS = IBATT = 0mA, V CEN = 5V, VPEN2 = 0V DC = unconnected, VUSB = V CEN = VUSUS = 5V DC unconnected, VUSB = V CEN = 5V, ISYS = 400mA When SYS regulation and charging stops, VUSB falling, 150mV hysteresis DC unconnected, VUSB = 5V, TA = +25NC DC unconnected, VUSB = 6V, VPEN2 = 5V, ISYS = 1mA to 400mA, VCEN = 5V DC unconnected, VUSB = 6V, VPEN2 = 5V, ISYS = 1mA to 1.2A, VCEN = 5V Input current ramp time Die temperature at when the charging current and input current limits are reduced ISYS reduction with die temperature (above +100NC) DC unconnected, VUSB = 5V, IVL = 0 to 5mA DC unconnected, VUSB = 5V, ILDO = 0mA LDO Output Voltage LDO Load Regulation VDC = 5V, USB unconnected, ILDO = 0mA DC and USB unconnected, VBATT = 4V, ILDO = 0mA ILDO = 0 to 30mA 3 3.234 3.234 3.234 MAX8934D only, RPSET = 2kI VPEN1 = 0V, VPEN2 = 5V VPEN1 = VPEN2 = 0V MAX8934A MAX8934B/MAX8934C/ MAX8934E MAX8934D 10 1350 450 80 5.2 4.29 4.29 3.95 6.8 4.0 6.9 1 0.9 190 0.22 50 1500 475 95 5.3 4.35 4.35 50 100 5 3.3 3.3 3.3 3.3 0.003 3.6 3.366 3.366 3.366 %/mA V 4.1 6.6 8 4.05 7.0 2 1.5 340 0.33 90 1650 500 100 5.4 4.4 4.4 Fs NC %/NC V V mA V V V V mA FA I mV CONDITIONS ISYS reduction with die temperature (above +100NC) IVL = 0 to 5mA, USB = unconnected 3 MIN TYP 5 3.3 3.6 MAX UNITS %/C V
MAX8934A-MAX8934E
SYS Regulation Voltage
Input Limiter Soft-Start Time Thermal-Limit Temperature Thermal-Limit Gain VL Voltage LDO LINEAR REGULATOR
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3
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring MAX8934A-MAX8934E
ELECTRICAL CHARACTERISTICS (continued)
(VDC = VPEN1 = VPEN2 = 5V, CEN = USUS = THMEN = GND, VBATT = 4V, VTHM = 1.65V, USB, THMSW, CHG, DONE, OT, DOK, UOK, FLT are unconnected, CCT = 0.068FF, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.) (Note 1) PARAMETER BATTERY CHARGER BATT-to-SYS On-Resistance BATT-to-SYS Reverse Regulation Voltage VDC = 0V, VBATT = 4.2V, ISYS = 1A VPEN1 = VPEN2 = 0V, ISYS = 200mA TA = +25NC, VTHM_T1 < VTHM < VTHM_T3 BATT Regulation Voltage--Safety IBATT = 0mA Region 1 (MAX8934A) TA = 0NC to +85NC, VTHM_T1 < VTHM < VTHM_T3 TA = +25NC, VTHM_T3 < VTHM < VTHM_T4 TA = 0NC to +85NC, VTHM_T3 < VTHM < VTHM_T4 TA = +25NC, VTHM_T2 < VTHM < VTHM_T3 TA = 0NC to +85NC, VTHM_T2 < VTHM < VTHM_T3 BATT Regulation Voltage--Safety IBATT = 0mA Region 2 TA = +25NC, VTHM_T1 < VTHM < VTHM_T2 or VTHM_T3 < VTHM < VTHM_T4 TA = 0NC to +85NC, VTHM_T1 < VTHM < VTHM_T2 or VTHM_T3 < VTHM < VTHM_T4 BATT Recharge Threshold-- Safety Region 1 (MAX8934A) BATT Recharge Threshold-- Safety Region 2 BATT Fast-Charge Current Range Change in VBATT from DONE to fastcharge restart Change in VBATT from DONE to fastcharge restart RISET = 10kI to 2kI VTHM_T1 < VTHM < VTHM_T3 VTHM_T3 < VTHM < VTHM_T4 VTHM_T2 < VTHM < VTHM_T3 VTHM_T1 < VTHM < VTHM_T2 or VTHM_T3 < VTHM < VTHM_T4 50 4.175 4.158 4.05 4.034 4.175 4.158 0.04 75 4.2 4.2 4.075 4.075 4.2 4.2 0.08 105 4.225 4.242 V 4.1 4.1 4.225 4.242 V I mV CONDITIONS MIN TYP MAX UNITS
4.05
4.075
4.1
4.034 -145 -120 -145 -120 0.3
4.075 -104 -80 -104 -80
4.1 -65 -40 -65 -40 1.5 mV
mV
A
4
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Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring
ELECTRICAL CHARACTERISTICS (continued)
(VDC = VPEN1 = VPEN2 = 5V, CEN = USUS = THMEN = GND, VBATT = 4V, VTHM = 1.65V, USB, THMSW, CHG, DONE, OT, DOK, UOK, FLT are unconnected, CCT = 0.068FF, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.) (Note 1) PARAMETER CONDITIONS RISET = 2kI RISET = 4kI VSYS = 5.5V, VTHM_T2 < VTHM < VTHM_T4 (safety region 1) or VTHM_T1 < VTHM < VTHM_T4 (safety region 2) BATT Charge Current Accuracy RISET = 10kI RISET = 2kI, VBATT = 2.5V (prequal) RISET = 4kI, VBATT = 2.5V (prequal) RISET = 10kI, VBATT = 2.5V (prequal) RISET = 2kI RISET = 4kI VSYS = 5.5V, VTHM_T1 < VTHM < VTHM_T2 (safety region 1) RISET = 10kI RISET = 2kI, VBATT = 2.5V (prequal) RISET = 4kI, VBATT = 2.5V (prequal) RISET = 10kI, VBATT = 2.5V (prequal) ISET Output Voltage Charger Soft-Start Time BATT Prequal Threshold RISET = 4kI, IBATT = 500mA (VISET = 1.5V at full charge current) VTHM_T2 < VTHM < VTHM_T4 Charge-current ramp time VBATT rising, 180mV hysteresis No DC or USB power connected, THMEN = low, VCEN = 5V BATT Input Current VBATT = 4.2V, ILDO = 0 No DC or USB power connected, THMEN = high, V CEN = 5V DC or USB power connected, V CEN = 5V DONE Threshold as a Percentage of Fast-Charge Current IBATT decreasing 2.9 0.9 675 337.5 130 100 50 MIN 1350 675 270 130 50 TYP 1500 750 300 150 75 30 750 375 150 150 75 30 1 1.5 3 5 3.1 12 1.1 V ms V 825 412.5 170 200 100 mA MAX 1650 825 330 170 100 UNITS
MAX8934A-MAX8934E
12 0.003
25 2
FA
10
%
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5
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring MAX8934A-MAX8934E
ELECTRICAL CHARACTERISTICS (continued)
(VDC = VPEN1 = VPEN2 = 5V, CEN = USUS = THMEN = GND, VBATT = 4V, VTHM = 1.65V, USB, THMSW, CHG, DONE, OT, DOK, UOK, FLT are unconnected, CCT = 0.068FF, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.) (Note 1) PARAMETER Maximum Prequal Time Maximum Fast-Charge Time Maximum Top-Off Time Timer Accuracy Timer Extend Threshold Timer Suspend Threshold Percentage of fast-charge current below where the timer clock operates at half-speed Percentage of fast-charge current below where timer clock pauses -2.2 ICHG = 0A, when charging is suspended, 2NC hysteresis 73.9 8 64.5 42.8 THM Hot Threshold (T3) VBATT_REG reduced (safety region 1), 2.5NC hysteresis 32.1 57 22.4 71 OT asserts low, 5NC hysteresis 15.5 CONDITIONS From CEN falling to end of prequal charge, VBATT = 2.5V From CEN falling to FLT falling MAX8934A/MAX8934C/MAX8934E MAX8934B/MAX8934D -20 50 20 MIN TYP 30 300 15 60 +20 MAX UNITS min min s min % % %
THERMISTOR MONITOR (Beta = 3477) (Note 2) THM Cold No-Charge Threshold (T1) 0 74.4 10 65 45 32.4 60 22.7 75 15.8 +2.4 75.1 12 65.5 47.5 32.8 63.5 23 80 16 NC % of THMSW NC % of THMSW NC % of THMSW NC % of THMSW NC % of THMSW NC % of THMSW NC % of THMSW
THM Cold Threshold (T2)
ICHG reduced (safety region 1 only), VBATT_REG reduced (safety region 2 only), 2NC hysteresis
THM Hot No-Charge Threshold (T4) THM Hot Overtemperature Threshold (TOT)
ICHG = 0mA, when charging is suspended, 3NC hysteresis
THERMISTOR MONITOR (Beta = 3964) (Note 3) THM Cold No-Charge Threshold (T1) -2.1 ICHG = 0A, when charging is suspended, 2NC hysteresis 76.4 8.2 66.2 0 77.2 10 67 +2.4 77.9 12 67.6
THM Cold Threshold (T2)
ICHG reduced (safety region 1 only), VBATT_REG reduced (safety region 2), 2NC hysteresis
6
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Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring
ELECTRICAL CHARACTERISTICS (continued)
(VDC = VPEN1 = VPEN2 = 5V, CEN = USUS = THMEN = GND, VBATT = 4V, VTHM = 1.65V, USB, THMSW, CHG, DONE, OT, DOK, UOK, FLT are unconnected, CCT = 0.068FF, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.) (Note 1) PARAMETER THM Hot Threshold (T3) CONDITIONS VBATT_REG reduced, safety region 1, 2.5NC hysteresis MIN 42.8 29.8 57 19.5 71 OT asserts low, 5NC hysteresis TA = +25NC TA = +85NC TA = +25NC TA = +85NC VLDO 0.05 1.3 0.4 50 TA = +25NC TA = +85NC TA = +25NC TA = +85NC 0.001 0.01 25 0.001 0.01 100 1 1 -0.2 12.6 -1 TYP 45 30 60 19.8 75 12.9 +0.001 0.01 +0.001 0.01 +1 MAX 47.5 30.6 63.5 20.1 80 13.1 +1 UNITS NC % of THMSW NC % of THMSW NC % of THMSW FA FA V
MAX8934A-MAX8934E
THM Hot No-Charge Threshold (T4) THM Hot Discharge Threshold (TOT) THM Input leakage THMSW Output Leakage THMSW Output Voltage High
ICHG = 0mA, when charging is suspended, 3NC hysteresis
THM = GND or LDO THMSW = GND Sourcing 1mA
LOGIC I/O: PEN1, PEN2, CHG, FLT, DONE, DOK, UOK, USUS, THMEN) High level Logic-Input Thresholds Low level Hysteresis Logic-Input Leakage Current Logic-Low Output Voltage Logic-High Output Leakage Current VIN = 0 to 5.5V Sinking 1mA VOUT = 5.5V V mV FA mV FA
Note 1: Limits are 100% production tested at TA = +25NC. Limits over the operating temperature range are guaranteed by design. Note 2: NC includes external NTC thermistor error. % of THMSW excludes thermistor beta error and external pullup error. NTC thermistor assumed to be 10kI nominal, part number Vishay NTHS0603N02N1002FF, external pullup resistor = 10kI. Note 3: NC includes external NTC thermistor error. % of THMSW excludes thermistor beta error and external pullup error. NTC thermistor assumed to be 100kI Q1% nominal, part number Vishay NTHS0603N01N1003FF, external pullup resistor = 100kI Q1%.
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7
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring MAX8934A-MAX8934E
Typical Operating Characteristics
(MAX8934A, TA = +25NC, circuit of Figure 2, VDC = 6V, VBATT = 3.6V, thermistor Beta = 3964, unless otherwise noted. Negative battery current indicates charging.)
USB OPERATING SUPPLY CURRENT vs. USB VOLTAGE (CHARGER ENABLED)
MAX8934A/B/C toc01
USB OPERATING SUPPLY CURRENT vs. USB VOLTAGE (CHARGER DISABLED)
MAX8934A toc02
USB SUSPEND CURRENT vs. USB VOLTAGE
VBATT = 4.2V, USUS = 1
MAX8934A/B/C toc03
1200 USB OPERATIN SUPPLY CURRENT (uA) 1000 800 600 400 200
900 USB OPERATING SUPPLY CURRENT (uA) 800 700 600 500 400 300 200 100 0 0 1 2 3 4 ENTERING OVLO VUSB RISING VUSB FALLING VBATT = 4.2V, VUSUS = 0V CEN = 1 ISYS = 0A PEN1 = X, PEN2 = 1
250 USB QUIESCENT CURRENT (FA) 200 150 100 50 0
VBATT = 4.2V, VUSUS = 0V CHARGER IN DONE MODE ISYS = 0A VUSB RISING VUSB FALLING
ENTERING OVLO
0 0 1 2 3 4 5 6 7 8 USB VOLTAGE (V)
5
6
7
8
0
1
2
3
4
5
6
7
8
USB VOLTAGE (V)
USB VOLTAGE (V)
BATTERY INPUT CURRENT vs. BATTERY VOLTAGE (USB DISCONNECTED)
MAX8934A toc04
BATTERY INPUT CURRENT vs. TEMPERATURE
MAX8934A toc05
CHARGE CURRENT vs. BATTERY VOLTAGE (100mA USB)
90 80 CHARGE CURRENT (mA) 70 60 50 40 30 20 10 0 0 1 2 3 4 5 BATTERY VOLTAGE (V)
MAX8934A/B/C toc06
14 BATTERY INPUT CURRENT (uA) 12 THMEN = 1 10 8 6 4 THMEN = 0 2 0 0 1 2 3 4
5.0 4.9 BATTERY INPUT CURRENT (uA) 4.8 4.7 4.6 4.5 4.4 4.3 4.2 4.1 4.0 VBATT = 4V, THMEN = 0, ILDO = 0 USB AND DC UNCONNECTED
100
VUSB = 5V PEN1 = X, PEN2 = 0 VBATT RISING VBATT FALLING
5
-40
-15
10
35
60
85
BATTERY VOLTAGE (V)
TEMPERATURE (C)
CHARGE CURRENT vs. BATTERY VOLTAGE (500mA USB)
MAX8934A/B/C toc07
CHARGE CURRENT vs. BATTERY VOLTAGE (1A DC)
VDC = 5V PEN1 = 1, PEN2 = X VBATT RISING VBATT FALLING
MAX8934A/B/C toc08
500 450 400 CHARGE CURRENT (mA) 350 300 250 200 150 100 50 0 0 1 2 3 4
1200 1000 CHARGE CURRENT (mA) 800 600 400 200 0
VUSB = 5V PEN1 = X, PEN2 = 1 VBATT RISING VBATT FALLING
5
0
1
2
3
4
5
BATTERY VOLTAGE (V)
BATTERY VOLTAGE (V)
8
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Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring
Typical Operating Characteristics (continued)
(MAX8934A, TA = +25NC, circuit of Figure 2, VDC = 6V, VBATT = 3.6V, thermistor Beta = 3964, unless otherwise noted. Negative battery current indicates charging.)
NORMALIZED CHARGE CURRENT vs. AMBIENT TEMPERATURE (LOW IC POWER DISSIPATION)
MAX1960 toc09
MAX8934A-MAX8934E
BATTERY REGULATION VOLTAGE vs. TEMPERATURE
BATTERY REGULATION VOLTAGE (V) 4.215 4.210 4.205 4.200 4.195 4.190 4.185 4.180 4.175 4.170 -40 -15 10 35 60 85 BATTERY VOLTAGE (V)
MAX8934A toc10
1.0100 NORMALIZED CHARGE CURRENT 1.0075 1.0050 1.0025 1.0000 0.9975 0.9950 0.9925 0.9900 -40 -15 10
VUSB = 5V, VBATT = 4V
4.220
35
60
85
AMBIENT TEMPERATURE (C)
SYS OUTPUT VOLTAGE vs. USB VOLTAGE
MAX8934A/B/C toc11
SYS OUTPUT VOLTAGE vs. DC VOLTAGE
5.2 SYS OUTPUT VOLTAGE (V) 5.0 4.8 4.6 4.4 4.2 4.0 MAX8934A MAX8934B- MAX8934E
5.2
SYS OUTPUT VOLTAGE (V)
VBATT = 4.0V NO SYS LOAD
VBATT = 4.0V NO SYS LOAD
5.0 4.8 4.6 4.4 4.2 4.0 0 1 2 3 4 5 6 7 MAX8934A MAX8934B- MAX8934E
8
0
2
4
6
8
10
12
14
USB VOLTAGE (V)
DC VOLTAGE (V)
SYS OUTPUT VOLTAGE vs. SYS OUTPUT CURRENT (USB AND DC DISCONNECTED)
MAX8934A/B/C toc13
SYS OUTPUT VOLTAGE vs. SYS OUTPUT CURRENT (DC)
MAX8934A/B/C toc14
4.5 4.4 SYS OUTPUT VOLTAGE (V) 4.3 4.2 4.1 4.0 3.9 3.8 3.7 3.6 0 0.5 1.0 1.5
5.5 5.1 4.7 4.3 3.9 3.5
VBATT = 4.0V THE SLOPE OF THIS LINE SHOWS THAT THE BATT-TO-SYS RESISTANCE IS 40mI.
SYS OUTPUT VOLTAGE (V)
VDC = 6V VDC = 5V
MAX8934A
VDC = 6V
MAX8934B- MAX8934E VDC = 5V VBATT = 4V, PEN1 = 1, PEN2 = X CEN = 1 0 0.5 1.0 1.5 2.0 2.5 3.0
2.0
SYS OUTPUT CURRENT (A)
SYS OUTPUT CURRENT (A)
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MAX8934A/B/C toc12
5.4
5.4
9
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring MAX8934A-MAX8934E
Typical Operating Characteristics (continued)
(MAX8934A, TA = +25NC, circuit of Figure 2, VDC = 6V, VBATT = 3.6V, thermistor Beta = 3964, unless otherwise noted. Negative battery current indicates charging.)
SYS OUTPUT VOLTAGE vs. SYS OUTPUT CURRENT (USB)
MAX8934A/B/C toc15a
SYS OUTPUT VOLTAGE vs. SYS OUTPUT CURRENT (USB)
5.3
SYS OUTPUT VOLTAGE (V)
5.3
SYS OUTPUT VOLTAGE (V)
5.1 4.9 4.7 4.5 4.3 4.1 3.9 3.7 3.5 0 0.5 1.0 1.5
VBATT = 4.0V, VUSB = 5.0V CEN = 1
5.1 4.9 4.7 4.5 4.3 4.1 3.9 3.7 3.5
VBATT = 4.0V, VUSB = 5.0V CEN = 1 0.14A, MAX8934B/MAX8934C/ MAX8934D PEN1 = 0, PEN2 = 0 0.5A, MAX8934B/MAX8934C/ MAX8934D PEN1 = 0, PEN2 = 0 1.5A, MAX8934D PEN1 = 1, PEN2 = 1
0.5A, MAX8934A, PEN1 = 0, PEN2 = 1
0.1A, MAX8934A, PEN1 = 0, PEN2 = 0
2.0 2.5 3.0
0
0.5
1.0
1.5
2.0
2.5
3.0
SYS OUTPUT CURRENT (A)
SYS OUTPUT CURRENT (A)
VL OUTPUT VOLTAGE vs. DC VOLTAGE
MAX8934A/B/C toc16
CHARGE PROFILE--820mAh BATTERY USB INPUT--500mA CHARGE
500 450 400 BATTERY CURRENT (mA) 350 300 250 200 150 100 50 0 2.0 0 20 40 60 80 100 120 140 TIME (min) 2.5 VBATT IBATT 3.5 3.0 4.0 BATTERY VOLTAGE (V)
MAX8934A toc17
3.5 3.0 VL OUTPUT VOLTAGE (V) 2.5 2.0 1.5 1.0 0.5 0 0 2 4 6 8 10 12
IVL = 5mA
IVL = 0mA
14
DC VOLTAGE (V)
CHARGE PROFILE--820mAh BATTERY ADAPTER INPUT--1A CHARGE
MAX8934A toc18
DC CONNECT WITH USB CONNECTED (RSYS = 22I)
4.5 4.0 BATTERY VOLTAGE (V) 3.5 3.0 VSYS IDC
1.2 1.0 BATTERY CURRENT (mA) 0.8 0.6 IBATT 0.4 0.2 0 0 10 20 30 40 50 60 70 VBATT
MAX8934A/B/C toc19
4.2V CDC CHARGING 0A
5.3V CSYS CHARGING 1.24A
5V/div 1A/div
IUSB
475mA BATTERY CHARGER SOFT-START
2.5 2.0 1.5 80
IBATT
-190mA 0A -1A
400Fs/div
TIME (min)
10
_____________________________________________________________________________________
MAX8934A/B/C toc15b
5.5
5.5
4.5
500mA/div
1A/div
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring
Typical Operating Characteristics (continued)
(MAX8934A, TA = +25NC, circuit of Figure 2, VDC = 6V, VBATT = 3.6V, thermistor Beta = 3964, unless otherwise noted. Negative battery current indicates charging.)
DC CONNECT WITH NO USB (RSYS = 22I)
VBATT VSYS
MAX8934A-MAX8934E
MAX8934A/B/C toc20
DC DISCONNECT WITH NO USB (RSYS = 22I)
5V/div VBATT VSYS 5V/div
MAX8934A/B/C toc21
3.6V 3.5V 5V 1.2A
3.6V 3.5V
5V/div 5V/div 1A/div
IDC
CDC CHARGING 0A 160mA
1A/div
IDC
1A 0A 160mA
IBATT
0mA BATTERY CHARGER SOFT-START
400Fs/div
-1A
1A/div
IBATT
-820mA -IBATT = CHARGING
400Fs/div
1A/div
USB CONNECT WITH NO DC (RSYS = 22I)
VUSB
MAX8934A/B/C toc22
USB DISCONNECT WITH NO DC (RSYS = 22I)
5V/div 500mA/div VUSB IUSB
MAX8934A/B/C toc23
5V CSYS CHARGING
IUSB
5V 475mA
5V/div
0A CUSB CHARGING 5V
475mA
3V 0mA
500mA/div
VSYS VUOK VCHG IBATT
3.6V 3.3V 3.3V +160mA
4.2V
5V/div 5V/div 5V/div
VSYS VUOK VCHG IBATT
3.9V
3.6V 3.3V 3.3V
5V/div 5V/div 5V/div 500mA/div
BATTERY CHARGER SOFT-START
-260mA
500mA/div
-260mA
+160mA
200Fs/div
200Fs/div
USB SUSPEND (RSYS = 22I)
VUSUS IUSB
MAX8934A/B/C toc24
USB RESUME (RSYS = 22I)
5V/div 500mA/div 5V/div 5V/div VUSUS IUSB VSYS VCHG IBATT
MAX8934A/B/C toc25
0V 475mA 4.2V
3V 0A 3.2V
3V 0A 3.3V
0V 475mA 4.6V 4.2V
5V/div 500mA/div 5V/div 5V/div
VSYS VCHG IBATT
3.3V 0A
3.3V
500mA/div VUSB = 5V
3.3V 0A BATTERY CHARGER SOFT-START
200Fs/div VUSB = 5V
500mA/div
200Fs/div
______________________________________________________________________________________
11
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring MAX8934A-MAX8934E
Typical Operating Characteristics (continued)
(MAX8934A, TA = +25NC, circuit of Figure 2, VDC = 6V, VBATT = 3.6V, thermistor Beta = 3964, unless otherwise noted. Negative battery current indicates charging.)
LDO OUTPUT VOLTAGE vs. LDO OUTPUT CURRENT (USB DISCONNECTED)
MAX8934A/B/C toc26
LDO STARTUP WAVEFORMS
MAX8934A/B/C toc27
3.35 3.30 LDO OUTPUT VOLTAGE (V) 3.25 3.20 3.15 3.10 3.05 3.00 2.95 0
VBATT = 4.0V
ILDO = 0 VBATT
3.6V
2V/div 2V/div
DC UNCONNECTED VDC = 5.0V
VLDO
3.3V
IBATT
50mA/div
25
50 75 100 125 150 LDO OUTPUT CURRENT (mA)
175
400Fs/div
LDO OUTPUT VOLTAGE vs. BATTERY VOLTAGE
MAX8934A/B/C toc28
ALWAYS-ON LDO POWER-SUPPLY REJECTION RATIO vs. FREQUENCY
-5 -10 -15 PSRR (dB) -20 -25 -30 -35 -40 -45 -50 0.1 1 10 100 FREQUENCY (kHz) VSYS = 3.6V ILDO = 10mA RESISTIVE LOAD
MAX8934A toc29 MAX8934A/B/C toc31
3.5 3.0 LDO OUTPUT VOLTAGE (V) 2.5 2.0 1.5 1.0 0.5 0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
0
VBATT FALLING VBATT RISING
4.0
BATTERY VOLTAGE (V)
LDO NOISE DENSITY vs. FREQUENCY
800 OUTPUT NOISE (nV/Hz) 700 600 500 400 300 200 100 0 0.01 0.1 1 10 100 1000 10,000 IBATT VBATT VBATT = 3.8V, ILDO = 10mA RESISTIVE LOAD
MAX8934A toc30
900
THM NORMAL TO THM COLD (< T2) TRANSITION
VTHM
500mV/div
2.2V
3.6V
2V/div
1A 500mA
500mA/div
10ms/div
FREQUENCY (kHz)
12
_____________________________________________________________________________________
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring
Typical Operating Characteristics (continued)
(MAX8934A, TA = +25NC, circuit of Figure 2, VDC = 6V, VBATT = 3.6V, thermistor Beta = 3964, unless otherwise noted. Negative battery current indicates charging.)
THM NORMAL TO THM HOT (> T3) TRANSITION
MAX8934A/B/C toc32
MAX8934A-MAX8934E
THM NORMAL TO THM HOT NO CHARGE (> T4) TRANSITION
MAX8934A/B/C toc33
0.65V
VTHM 500mV/div VTHM 500mV/div
1.0V
VBATT
4.2V 4.075V
200mV/div 500mA/div VBATT
4.075V 0V
2V/div
4.2V
IBATT
940mA HP6060B ELECTRONIC LOAD SET TO CC MODE
10ms/div
IBATT
100mA 0mA HP6060B ELECTRONIC LOAD SET TO CC MODE
20ms/div 100mA/div
THM NORMAL TO THM HOT THRESHOLD DISCHARGE TOT
VTHM VOT
THM NORMAL TO THM COLD NO CHARGE (< T1) TRANSITION
MAX8934A/B/C toc35
MAX8934A toc34
2V/div
3V
4.025V
2V/div
VTHM
500mV/div
3.6V
VBATT
2.2V
2.54V
2V/div
VBATT
3.6V
2V/div IBATT
1A 500mA 0mA
500mA/div
VSYS
3.6V
2V/div
4ms/div
10ms/div
______________________________________________________________________________________
13
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring MAX8934A-MAX8934E
Pin Description
PIN 1 NAME DONE FUNCTION Charge Complete Output. The DONE active-low, open-drain output pulls low when the charger enters the DONE state. The charger current = 0mA when DONE is low. See Figure 8. DC Power Input. DC is capable of delivering up to 2A to SYS. DC supports both AC adapter and USB inputs. The DC current limit is set with PEN1, PEN2, and RPSET. See Table 2. Both DC pins must be connected together externally. Connect a 10FF ceramic capacitor from DC to GND. The DC inputs should be grounded if not used. Active-Low Charger Enable Input. Connect CEN to GND or drive low with a logic signal to enable battery charging when a valid source is connected at DC or USB. Drive high with a logic signal to disable battery charging. Input Limit Control 1. See Table 2a for complete information (MAX8934A/MAX8934B/MAX8934C/ MAX8934E). Input Limit Control 1. See Table 2b for complete information (MAX8934D). 6 PEN2 Input Limit Control 2. See Table 2a for complete information (MAX8934A/MAX8934B/MAX8934C/ MAX8934E). Input Limit Control 2. See Table 2b for complete information (MAX8934D). 7 PSET DC Input Current-Limit Setting. Connect a resistor from PSET to GND to program the DC current limit up to 2A (3000/RPSET). Internal Logic LDO Output Bypass Pin. Provides 3.3V when DC or USB is present. Connect a 0.1FF ceramic capacitor from VL to GND. VL powers the internal circuitry and provides up to 5mA to an external load. Ground. Both GND pins must be connected together externally. Charge Timer Program Input. A capacitor from CT to GND sets the maximum prequal and fast-charge timers. Connect CT to GND to disable the timer. Charge Current-Limit Setting. A resistor (RISET) from ISET to GND programs the fast-charge charge current up to 1.5A (3000/RISET). The prequal charge current is 10% of the set fast-charge charge current. USB Suspend Digital Input. As shown in Table 2a, driving USUS high suspends the DC or USB inputs if they are configured as a USB power input (MAX8934A/MAX8934B/MAX8934C/MAX8934E). USB Suspend Digital Input. As shown in Table 2b, driving USUS high suspends the DC or USB inputs if they are configured as a USB power input (MAX8934D). Thermistor Input. Connect a negative temperature coefficient (NTC) thermistor with good thermal contact with the battery from THM to GND. Use a thermistor with Beta = 3964. Connect a resistor of equal resistance to the thermistor resistance at +25C from THM to THMSW so that the battery temperature can be monitored, and the fast-charge current and/or the charge termination voltage is automatically adjusted, in accordance with safety region 1 or safety region 2 of the JEITA specification. Thermistor Enable Input. THMEN controls THMSW by connecting the external thermistor pullup resistor and the thermistor monitoring circuit to LDO. Drive THMEN high to enable the thermistor circuit in discharge mode and to connect the external thermistor pullup resistor. Drive THMEN low to disconnect the external thermistor pullup resistor and to disable the thermistor monitoring circuit to conserve battery energy when not charging.
2, 3
DC
4
CEN
5
PEN1
8 9, 13 10
VL GND CT
11
ISET
12
USUS
14
THM
15
THMEN
14
_____________________________________________________________________________________
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring
Pin Description (continued)
PIN NAME FUNCTION Thermistor Pullup Supply Switch. Drive THMEN high to enable the THMSW, shorting the THMSW output to LDO. Drive THMEN low to open the THMSW switch. THMSW is always on when a valid input source is present and the battery is being charged. When no input source is present, THMSW is controlled by THMEN. THMSW is also active when the battery is being discharged, so that the battery temperature can be monitored for an overtemperature condition. Always-On Linear Regulator Output. LDO is the output of an internal always-on 3.3V LDO that provides power to external circuitry. The LDO output provides up to 30mA of current for indicator LEDs or other loads. LDO remains active even when only a battery is present, so that the thermistor monitor circuitry can be activated when the battery is being discharged, and other circuitry can remain powered. Connect a 1FF ceramic capacitor from LDO to GND. USB Power Input. USB is capable of delivering up to 0.5A to SYS in the MAX8934A/MAX8934B/ MAX8934C/MAX8934E. The USB current limit is set with PEN2 and USUS. See Table 2a. In the MAX8934D, USB is capable of delivering up to 1.5A to SYS. Both USB pins must be connected together externally. Connect a 4.7FF ceramic capacitor from USB to GND. Battery Connection. Connect the positive terminal of a single-cell Li+ battery to BATT. The battery charges from SYS when a valid source is present at DC or USB. BATT powers SYS when neither DC nor USB power is present, or when the SYS load exceeds the input current limit. Both BATT pins must be connected together externally. Charger Status Output. The CHG active-low, open-drain output pulls low when the battery is in fast charge or prequal. Otherwise, CHG is high impedance. System Supply Output. SYS is connected to BATT through an internal 40mI system load switch when DC or USB are invalid, or when the SYS load is greater than the input current limit. When a valid voltage is present at DC or USB, SYS is limited to 5.3V (MAX8934A) or 4.35V (MAX8934B/ MAX8934C/MAX8934D/MAX8934E). When the system load (ISYS) exceeds the DC or USB current limit, SYS is regulated to 68mV below VBATT and both the input and the battery service the SYS load. Bypass SYS to GND with a 10FF ceramic capacitor. Both SYS pins must be connected together externally. Battery Overtemperature Flag. The OT active-low, open-drain output pulls low when THMEN is high and the battery temperature is R +75NC. DC Power-OK Output. The DOK active-low, open-drain output pulls low when a valid input is detected at DC. USB Power-OK Output. The UOK active-low, open-drain output pulls low when a valid input is detected at USB. Fault Output. The FLT active-low, open-drain output pulls low when the battery timer expires before prequal or fast charge complete. Exposed Pad. Connect the exposed pad to GND. Connecting the exposed pad does not remove the requirement for proper ground connections to the appropriate pins.
MAX8934A-MAX8934E
16
THMSW
17
LDO
18, 19
USB
20, 21
BATT
22
CHG
23, 24
SYS
25 26 27 28 --
OT DOK UOK FLT EP
______________________________________________________________________________________
15
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring MAX8934A-MAX8934E
OT DC DC DC POWER MANAGEMENT
LDO
SYS SYS Li+ BATTERY CHARGER AND SYS LOAD SWITCH
PWR OK
3.3V ALWAYS-ON LOW-IQ LDO CURRENTLIMITED VOLTAGE REGULATOR
DOK
CHARGER CURRENT AND VOLTAGE CONTROL
ISET BATT BATT
SET INPUT LIMIT
VL
VL LDO FOR IC POWER USB POWER MANAGEMENT
THERMISTOR MONITOR (SEE FIGURE 5) THM THMSW
T
USB
PWR OK CURRENTLIMITED VOLTAGE REGULATOR CHG CHARGE TERMINATION AND MONITOR
THMEN THERMAL REGULATION
UOK
CHG DONE FLT
SET INPUT LIMIT PEN1 PEN2 USUS PSET GND EP INPUT AND CHARGER CURRENT-LIMIT LOGIC CONTROL CHARGE TIMER
CT
MAX8934A- MAX8934E
CEN
Figure 1. Block Diagram
16
_____________________________________________________________________________________
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring MAX8934A-MAX8934E
TO LDO RPU 1MI CHARGE DONE ADAPTER CDC 10FF 1 DONE OT 25 28 27 26 RPU 4x 1MI OVERTEMPERATURE FAULT OUTPUT USB PWR OK DC PWR OK
2 DC 3 DC 5 OFF CHARGE ON 500mA 100mA RPSET 1.5kI 11 RISET 3kI CVL 0.1FF 9, 13 CCT 0.068FF THMSW ACTIVE DISABLED 10 15 16 14 100kI NTC 100kI 25C ISET 4 6 7 PEN1 CEN PEN2 PSET
MAX8934A- MAX8934E
FLT UOK DOK
SYS 23 SYS 24 1MI CHG 22 LDO CSYS 10FF
TO SYSTEM LOAD
CHARGE INDICATOR
BATT 20 BATT 21 CBATT 4.7FF 1-CELL Li+
8
VL
GND CT THMEN THMSW THM EP
USB 18 USB 19 17 CLDO 1FF 12 CUSB 4.7FF
1 2 3 4 5
VBUS DD+ ID GND
LDO
USUS
USB SUSPEND
Figure 2. Typical Application Circuit Using Separate DC and USB Connector
______________________________________________________________________________________
17
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring MAX8934A-MAX8934E
TO LDO RPU 1MI 1 DONE RPU 4x 1MI
5-PIN USB CONNECTOR VBUS DD+ ID GND 1 2 3 4 5
CHARGE DONE
2 DC CDC 10FF 3 DC
MAX8934A- MAX8934E
OT FLT UOK DOK
25 28 27 26
OVERTEMPERATURE FAULT OUTPUT USB PWR OK DC PWR OK
OFF CHARGE ON DC USB 500mA 100mA RPSET 1.5kI
4 5 6 7
CEN PEN1
SYS 23 SYS 24 1MI CHG 22 CSYS 10FF VLDO
TO SYSTEM LOAD
PEN2 PSET
CHARGE INDICATOR
BATT 20 BATT 21 CBATT 4.7FF 1-CELL Li+
11 RISET 3kI CVL 0.1FF CCT 0.068FF THMSW ACTIVE DISABLED
ISET USB 18 VL USB 19 GND CT THMEN THMSW THM EP 12 LDO 17 CLDO 1FF USB SUSPEND
8
9, 13 10 15 16 14
USUS
100kI
NTC 100kI 25C
Figure 3. Typical Application Circuit Using a 5-Pin USB Connector or Other DC/USB Common Connector
18
_____________________________________________________________________________________
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring
Table 1. External Components List for Figures 2 and 3
COMPONENT (Figures 2 and 3) CDC CVL CSYS CBATT CCT CLDO RPU (x5) THM RTHMSW RPSET RISET FUNCTION DC filter capacitor VL filter capacitor SYS output bypass capacitors Battery bypass capacitor Charger timing capacitor LDO output capacitor Logic-output pullup resistors Negative TC thermistor THM pullup resistor DC input current-limit programming resistor Fast-charge current programming resistor PART NUMBER 10FF 10%, 16V X5R ceramic capacitor (0805) Taiyo Yuden EMK212BJ106KG 0.1FF 10%, 10V X5R ceramic capacitor (0402) Taiyo Yuden LMK105BJ104KV 10FF 10%, 6.3V X5R ceramic capacitor (0805) Taiyo Yuden JMK212BJ106KD 4.7FF 10%, 6.3V X5R ceramic capacitor (0805) Taiyo Yuden JMK212BJ475KD 0.068FF 10%, 16V X5R ceramic capacitor (0402) Taiyo Yuden EMK105BJ683KV 1FF 10%, 6.3V X5R ceramic capacitor (0402) Taiyo Yuden JMK105BJ105KV 1MI 5% resistor Vishay NTC Thermistor P/N NTHS0603N01N1003FF 100kI 1.5kI 1% for 2A limit 3kI 1% for 1A charging
MAX8934A-MAX8934E
Detailed Description
The MAX8934_ is a dual-input linear charger with Smart Power Selector that safely charges a single Li+/ Li-Poly cell in accordance with JEITA specifications. The MAX8934_ integrates power MOSFETs and control circuitry to manage power flow in portable devices. See Figure 1. The charger has two power inputs, DC and USB. These can be separately connected to an AC adapter output and a USB port, or the DC input could be a single power input that connects to either an adapter or USB. Logic inputs, PEN1 and PEN2, select the correct current limits for two-input or single-input operation. Figure 2 is the typical application circuit using separate DC and USB connectors. Figure 3 is the typical application circuit using a 5-pin USB connector or another DC/ USB common connector. In addition to charging the battery, the MAX8934_ also supplies power to the system through the SYS output. The charging current is also provided from SYS so that the set input current limit controls the total SYS current, where total SYS current is the sum of the system load current and the battery-charging current. SYS is powered from either the DC input pin or the USB sources
input pin. If both the DC and USB sources are connected, DC takes precedence. In some instances, there may not be enough adapter current or USB current to supply peak system loads. The MAX8934_ Smart Power Selector circuitry offers flexible power distribution from an AC adapter or USB source to the battery and system load. The battery is charged with any available power not used by the system load. If a system load peak exceeds the input current limit, supplemental current is taken from the battery. Thermal limiting prevents overheating by reducing power drawn from the input source. The MAX8934_ features an overvoltage limiter at SYS. If the DC or USB input voltage exceeds the SYS regulation voltage, VSYS does not follow VDC or VUSB, but remains at its regulation voltage. The MAX8934_ has numerous other charging and power-management features that are detailed in the following sections. A 3.3V ultra-low quiescent current, always-on LDO provides up to 30mA for indicator LEDs and for backup power to the system. This LDO powers the thermistor monitor circuitry and provides bias to the external pullup resistor for the thermistor.
*JEITA (Japan Electronics and Information Technology Industries Association) Standard, A Guide to the Safe Use of Secondary Lithium Ion Batteries on Notebook-Type Personal Computers, April 20, 2007. ______________________________________________________________________________________ 19
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring MAX8934A-MAX8934E
The MAX8934_ Smart Power Selector seamlessly distributes power among the external inputs, the battery, and the system load (see the Typical Operating Circuit). The basic functions performed are: U With both an external power supply (USB or adapter) and battery connected: U When the system load requirements are less than the input current limit, the battery is charged with residual power from the input. U When the system load requirements exceed the input current limit, the battery supplies supplemental current to the load. U When the battery is connected and there is no external power input, the system is powered from the battery. U When an external power input is connected and there is no battery, the system is powered from the external power input. A thermal-limiting circuit reduces the battery charge rate and external power-source current to prevent the MAX8934_ from overheating. An internal 40mI MOSFET connects SYS to BATT (Q3 in the Typical Operating Circuit) when no voltage source is available at DC or USB. When an external source is detected at DC or USB, this switch is opened and SYS is powered from the valid input source through the input limiter. The SYS-BATT switch also holds up SYS when the system load exceeds the input current limit. If that should happen, the SYS-BATT switch turns on so that the battery supplies additional SYS load current. If the system load continuously exceeds the input current limit, the battery does not charge, even though external power is connected. This is not expected to occur in most cases, since high loads usually occur only in short peaks. During these peaks, battery energy is used, but at all other times the battery charges. The input voltage limiter is essentially an LDO regulator. While in dropout, the regulator dissipates a small I2R loss through the 0.2I MOSFET (Q1 in the Typical Operating Circuit) between DC and SYS. With an AC adapter or USB source connected, the input limiter distributes power from the external power source to the system load and battery charger. In addition to the input limiter's primary function of passing power to the system
Smart Power Selector
and charger loads at SYS, it performs several additional functions to optimize use of available power. Input Voltage Limiting If an input voltage is above the overvoltage threshold (6.9V typ), the MAX8934_ enters overvoltage lockout (OVLO). OVLO protects the MAX8934_ and downstream circuitry from high-voltage stress up to 14V at DC and 8V at USB. In OVLO, VL remains on, the input switch that sees overvoltage (Q1, Q2, Typical Operating Circuit) opens, and the appropriate power-monitor output (DOK, UOK) is high impedance, and CHG is high impedance. If both DC and USB see overvoltage, both input switches (Q1 and Q2, Typical Operating Circuit) open and the charger turns off. The BATT-to-SYS switch (Q3, Typical Operating Circuit) closes, allowing the battery to power SYS. An input is also invalid if it is less than BATT, or less than the DC undervoltage threshold of 3.5V (falling). With an invalid input voltage, SYS connects to BATT through a 40mI switch (Q3, Typical Operating Circuit). Input Overcurrent Protection The current at DC and USB is limited to prevent input overload. This current limit can be selected to match the capabilities of the source, whether it is a 100mA or 500mA USB source, or an AC adapter. When the load exceeds the input current limit, SYS drops to 75mV below BATT and the battery supplies supplemental load current. Thermal Limiting The MAX8934_ reduces input limiter current by 5%/NC when its die temperature exceeds +100NC. The system load (SYS) has priority over the charger current, so lowering the charge current first reduces the input current. If the junction temperature still reaches +120NC in spite of charge current reduction, no input (DC or USB) current is drawn, the battery supplies the entire system load, and SYS is regulated at 75mV below BATT. Note that this on-chip thermal-limiting circuitry is not related to and operates independently from the thermistor input. Adaptive Battery Charging While the system is powered from DC, the charger draws power from SYS to charge the battery. If the charger load plus system load exceeds the input current limit, an adaptive charger control loop reduces charge current to prevent the SYS voltage from collapsing. Maintaining a higher SYS voltage improves efficiency and reduces power dissipation in the input limiter. The total current through the switch (Q1 or Q2 in the Typical Operating Circuit) is the sum of the load current at SYS and the battery charging current. The MAX8934A limiter clamps at 5.3V (4.35V for the MAX8934B/MAX8934C/
System Load Switch
Input Limiter
20
_____________________________________________________________________________________
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring
MAX9834D), so input voltages greater than 5.3V (4.35V for the MAX8934B/MAX8934C/MAX8934E) can increase power dissipation in the limiter. The MAX8934_ input limiter power loss is (VDC - VSYS) x IDC, where VSYS may be as high as 5.3V for the MAX8934A or 4.35V for the MAX8934B-MAX8934E. The input limiter power loss is not less than 0.2I x IDC2. Also note that the MAX8934_ turns off when any input exceeds 6.9V (typ). USB or AC adapter output. Input and charger current limit are controlled by PEN1, PEN2, RPSET, and RISET, as shown in Tables 2a and 2b. When the AC adapter and USB have separate connectors, the adapter output connects to DC and the USB source connects to USB. PEN1 is permanently connected high (to DC or VL). The DC current limit is set by RPSET, while the USB current limit is set by PEN2 and USUS.
MAX8934A-MAX8934E
Separate Adapter and USB Connectors
DC and USB Connections and Current-Limit Options
Input Current Limit The input and charger current limits are set as shown in Tables 2a and 2b. It is often preferable to change the input current limit as the input power source is changed. The MAX8934_ facilitates this by allowing different input current limits for DC and USB as shown in Tables 2a and 2b. When the input current limit is reached, the first action taken by the MAX8934_ is to reduce the battery charge current. This allows the regulator to stay in dropout, or at 5.3V (MAX8934A), during heavy loads, thus reducing power dissipation. If, after the charge current is reduced to 0mA, the load at SYS still exceeds the input current limit, SYS voltage begins to fall. When the SYS voltage drops to BATT, the SYS-to-BATT switch turns on, using battery power to support the system load during the load peak. The MAX8934_ features flexible input connections (at the DC and USB input pins) and current-limit settings (set by PEN1, PEN2, PSET, and ISET) to accommodate nearly any input power configuration. However, it is expected that most systems use one of two external power schemes: separate connections for USB and an AC adapter, or a single connector that accepts either
POWER SOURCE AC adapter at DC input USB power at DC input USB power at USB input; DC unconnected DC and USB unconnected
When a single common connector is used for both AC adapter and USB sources, the DC input is used for both input sources. The unused USB inputs should be grounded when an AC adapter is connected at DC, PEN1 should be pulled high to select the current limit set by RPSET. When a USB source is connected, PEN1 should be low to select 500mA, 100mA, or USB suspend (further selected by PEN2 and USUS). PEN1 can be pulled up by the AC adapter power to implement hardware adapter/USB selection. Driving USUS high when PEN1 is low turns off charging, as well as the SYS output and reduces input current to 190FA to accommodate USB suspend mode. DOK is an open-drain output that pulls low when the DC input has valid power. UOK is an open-drain output that pulls low when the USB input has valid power. A valid input for DC or USB is between 4.1V and 6.6V. If a single power-OK output is preferred, DOK and UOK can be
Single Common Connector for USB or Adapter
USB Suspend
Power Monitor Outputs (UOK, DOK)
Table 2a. Input Limiter Control Logic (MAX8934A/MAX8934B/MAX8934C/MAX8934E)
DOK L L L L H H H H UOK X X X X L L L H PEN1 H L L L X X X X PEN2 X H L X H L X X USUS X L L H L L H X No DC input DC INPUT CURRENT LIMIT 3000V/RPSET 475mA 95mA USB suspend 475mA 95mA USB suspend No USB input USB INPUT CURRENT LIMIT USB input off; DC input has priority MAXIMUM CHARGE CURRENT* 3000V/RISET 475mA 95mA 0 3000V/RISET 0 0
*Charge current cannot exceed the input current limit. Charge may be less than the maximum charge current if the total SYS load exceeds the input current limit. ______________________________________________________________________________________ 21
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring MAX8934A-MAX8934E
Table 2b. Input Limiter Control Logic (MAX8934D)
FEATURE Absolute Maximum Rating Input Current Limit DC INPUT 16V Set by RPSET, PEN1, PEN2, and USUS; 2A (max) UOK PEN1 PEN2 USB INPUT 9V Set by RPSET, PEN1, PEN2, and USUS; 1.5A (max) USUS DC INPUT CURRENT LIMIT 3000V/RPSET 3000V/RPSET 475mA 95mA USB suspend 3000V/RPSET 600V/RPSET 475mA No DC input 95mA USB suspend No USB input USB Input Off; DC input has priority NOTES -- PSET sets the same input current limit for DC and USB paths. USB INPUT CURRENT LIMIT MAXIMUM CHARGE CURRENT 3000V/RISET 3000V/RISET 475mA 95mA 0 3000V/RISET 3000V/RISET 475mA 95mA 0 0
POWER SOURCE AC Adapter at DC
DOK
L L
X X X X X L L L L L H
H H L L L H H L L X X
X X H L X H L H L X X
X X L L H L L L L H X
USB Power at DC
L L L H H H H H
USB Power at USB; DC Open
DC and USB Open
H
wire-ORed together. The combined output then pulls low if either USB or DC is valid. To prevent input transients that can cause instability in the USB or AC adapter power source, the rate of change of input current and charge current is limited. When a valid DC or USB input is connected, the input current limit is ramped from zero to the set current-limit value (as shown in Tables 2a and 2b). If DC is connected with no USB power present, input current ramps in 1.5ms. If DC is connected with USB already present, input current ramps in 50Fs. When USB is connected with no DC present, input current also ramps in 50Fs. If USB is connected with DC already present, the USB input is ignored. If an adapter is plugged into DC while USB is already powered, the input current limit reramps from zero back up to the DC current limit so that the AC adapter does not see a load step. During this transition, if the input current limit is below the SYS load current, the battery supplies the additional current needed to support the load. Additionally, capacitance can be added to SYS to
Soft-Start
support the load during input power transitions. When the charger is turned on, charge current ramps from zero to the ISET current value in typically 1.5ms. Charge current also ramps when transitioning to fast-charge from prequal and when changing the USB charge current from 100mA to 500mA with PEN2. There is no dI/dt limiting, however, if ISET is changed suddenly using a switch at RISET. The battery charger state diagram is illustrated in Figure 8. With a valid DC or USB input, the battery charger initiates a charge cycle when the charger is enabled. It first detects the battery voltage. If the battery voltage is less than the BATT prequal threshold (3.0V), the charger enters prequal mode and charges the battery at 10% of the maximum fast-charge current. This reduced charge rate ensures that the maximum fast-charge current setting does not damage a deeply discharged battery. Once the battery voltage rises to 3.0V, the charger transitions to fast-charge mode and applies the maximum charge current. As charging continues, the battery voltage rises until it approaches the battery regulation volt-
Battery Charger
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Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring
age where charge current starts tapering down. When charge current decreases to 10% of the fast-charge current, the charger enters a brief 15s top-off, (60min for the MAX8934B and MAX8934D) and then charging stops. If the battery voltage subsequently drops below the recharge threshold, charging restarts and the timers reset. When CEN is low, the charger is on. When CEN is high, the charger turns off. CEN does not affect the SYS output. In many systems, there is no need for the system controller (typically a microprocessor) to disable the charger, because the MAX8934_ Smart Power Selector circuitry independently manages charging and adapter/ battery power hand-off. In these situations, CEN can be connected to ground. ISET adjusts charge current to match the capacity of the battery. A resistor from ISET to ground sets the maximum fast-charge current: ICHGMAX = 2000 x 1.5V/RISET = 3000V/RISET Determine the ICHGMAX value by considering the characteristics of the battery. It is not necessary to limit the charge current based on the capabilities of the expected AC adapter/USB charging input, the system load, or thermal limitations of the PCB. The MAX8934_ automatically adjusts the charging algorithm to accommodate these factors. In addition to setting the charge current, ISET can also be used to monitor the actual current charging the battery. See Figure 4. The ISET output voltage is: VISET = ICHG x 1.5V/ICHGMAX = ICHG x RISET/2000 where ICHGMAX is the set fast-charge current and ICHG is the actual battery charge current. A 1.5V output indicates the battery is being charged at the maximum set fast charge current; 0V indicates no charging. This voltage is also used by the charger control circuitry to set and monitor the battery current. Avoid adding more than 10pF capacitance directly to the ISET pin. If filtering of the charge-current monitor is necessary, add a resistor of 100kI or more between ISET and the filter capacitor to preserve charger stability. Note that the actual charge current can be less than the set fast-charge current when the charger enters voltage mode or when the input current limiter or thermal limiter
MAX8934A-MAX8934E
MONITORING THE BATTERY CHARGE CURRENT WITH VISET
1.5
VISET (V)
Charge Enable (CEN)
VISET
0
Setting the Charge Current
DISCHARGING 0 BATTERY CHARGING CURRENT (A) 2000 (1.5V/RISET)
Figure 4. Monitoring the Battery Charge Current with VISET
reduces charge current. This prevents the charger from overloading the input source or overheating the system. When the charge current falls to the termination threshold and the charger is in voltage mode, charging is complete. Charging continues for a brief 15s top-off period (60min for the MAX8934B and MAX8934D) and then enters the DONE state where charging stops. The DONE current threshold (IDONE) is set to 10% of the fastcharge current setting. Note that if charge current falls to IDONE as a result of the input or thermal limiter, the charger does not enter the DONE state. For the charger to enter the DONE state, the charge current must be less than ITERM, the charger must be in voltage mode, and the input or thermal limiter must not be reducing the charge current. The charger exits the DONE state, and fast-charge resumes if the battery voltage subsequently drops 104mV or if CEN is cycled.
Charge Termination
Monitoring the Charge Current
Charge Status Outputs
Charge Output (CHG) CHG is an open-drain, active-low output that is low during charging. CHG is low when the battery charger is in its prequalification and fast-charge states. When charge current falls to the charge termination threshold and the charger is in voltage mode, CHG goes high impedance. CHG goes high impedance if the thermistor causes the charger to enter temperature suspend mode.
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Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring MAX8934A-MAX8934E
When the MAX8934_ is used with a microprocessor (FP), connect a pullup resistor between CHG and the logic I/O voltage to indicate charge status to the FP. Alternatively, CHG can sink up to 20mA for an LED indicator. Charge DONE Output (DONE) DONE is an open-drain, active-low output that goes low when charging is complete. The charger enters its DONE state 15s (60min for the MAX8934B and MAX8934D) after the charge current falls to the charge-termination threshold and the charger is in voltage mode. The charger exits the DONE state, and fast-charge resumes, if the battery voltage subsequently drops 104mV, or if input power or CEN is cycled. When the MAX8934_ is used in conjunction with a FP, connect a pullup resistor between DONE and the logic I/O voltage to indicate charge status to the FP. Alternatively, DONE can sink up to 20mA for an LED indicator. Fault Output (FLT) and Charge Timer FLT is an open-drain, active-low output that goes low during a battery fault. The fault state occurs when either the prequal or fast-charge timer expires. The prequal and fast-charge fault timers are set by CCT: The MAX8934_ thermistor monitor is configured to execute JEITA recommendations regarding Li+/Li-Poly battery charging by adjusting the fast charge current and/or the charge termination voltage accordingly (see Figures 6 and 7). Connect the THM input to an external negative temperature coefficient (NTC) thermistor to monitor battery or system temperature. Since the thermistor monitoring circuit employs an external bias resistor from THM to THMSW, the thermistor is not limited only to 10kI (at +25NC). Any thermistor resistance can be used as long as the value of RTHMSW is equivalent to the thermistor's +25NC resistance. The MAX8934_ THM thresholds are optimized for a thermistor Beta of 3964 or 3477 (see the Selector Guide). The general relation of thermistor resistance to temperature is defined by the following equation: R T = R 25 where: RT = The resistance in ohms of the thermistor at temperature T in Celsius R25 = The resistance in ohms of the thermistor at +25NC A = The material constant of the thermistor T = The temperature of the thermistor in NC Charging is suspended when the thermistor temperature is out of range (VTHM_T1 > VTHM > VTHM_T4). The charge timers are also suspended and hold their state but no fault is indicated. When the thermistor comes back into range, charging resumes and the charge timer continues from where it left off. The THMEN input controls THMSW and the thermistor monitor circuitry when the battery charger is disabled, providing the user with the means to minimize the battery current drain caused by the thermistor monitor. The THMEN input is ignored while the battery is charging, since the thermistor must be monitored at all times. While charging, the thermistor monitor is used to automatically adjust the charge termination voltage and/or the fast-charge current, depending on the sensed battery temperature and the safety region set at the factory. If the battery temperature exceeds the THM hot overtemperature threshold and THMEN is high, the OT flag pulls low. Typical systems connect OT to a FP input so that the system can safely shut down.
1 1 T + 273C 298C xe
Thermistor Monitor
PREQUAL: t PQ = 30min x
C CT 0.068FF
C CT 0.068FF
FAST CHARGE: t FC = 300min x
TOP - OFF: t TO = 15s (60 minutes for the MAX8934B and MAX8934D)
While in fast-charge mode, a large system load or device self-heating can cause the MAX8934_ to reduce charge current. Under these circumstances, the fast-charge timer adjusts to ensure that adequate charge time is still allowed. Consequently, the fast-charge timer is slowed by 2x if charge current is reduced below 50% of the programmed fast-charge level. If charge current is reduced to below 20% of the programmed level, the fast-charge timer is paused. The fast-charge timer is not adjusted if the charger is in voltage mode where charge current reduces due to current tapering under normal charging. To exit a fault state, toggle CEN or remove and reconnect the input source(s). Note also that thermistor out of range or on-chip thermal-limit conditions are not considered faults. When the MAX8934_ is used in conjunction with a FP, connect a pullup resistor between FLT and the logic I/O voltage to indicate fault status to the FP. Alternatively, FLT can sink up to 20mA for an LED indicator.
24
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Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring MAX8934A-MAX8934E
SYS
LOW-IQ, ALWAYS-ON 3.3V LDO LDO TRACKS SYS WHEN DC AND USB ARE NOT PRESENT, THE BATTERY IS BEING DISCHARGED, AND VBATT P 3.3V.
CHG
VINT CHG CHG CHARGER CONTROL T4 (60NC) THMEN THMSW RTHMSW
+
VINT VINT T3 (45NC) VINT
THM
OT THERMISTOR MONITOR
CHG
T
+
CHG VINT VINT T2 (10NC)
+ CHG VINT VINT
TOT (75NC)
+
CHG THMEN VINT VINT T1 (0NC)
+ CHG
Figure 5. Thermistor Monitor Details ______________________________________________________________________________________ 25
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring MAX8934A-MAX8934E
T1 BATT REGULATION VOLTAGE (V) (VBATT_REG) T2 T3 T4
BATT REGULATION VOLTAGE (V) (VBATT_REG) T1 T2 T3 T4
4.2 4.1 4.075 4.0 0 10 25 45 TEMPERATURE (NC) T3 60 85
4.2 4.1 4.075 4.0 0 10 25 45 60 TEMPERATURE (NC) T3 T4 85
C FAST-CHARGE CURRENT (ICHG)
T1
T2
T4
FAST-CHARGE CURRENT (ICHG)
C
T1
T2
0.5C
0.5C
0
10
25
45 TEMPERATURE (NC)
60
85
0
10
25
45 TEMPERATURE (NC)
60
85
Figure 6. Safety Region 1: Fast-Charge Currents and Charge Termination Voltages
Figure 7. Safety Region 2: Fast-Charge Currents and Charge Termination Voltages
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Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring MAX8934A-MAX8934E
NOT READY UOK AND DOK = HIGH-Z CHG = HIGH-Z FLT = HIGH-Z DONE = HIGH-Z ICHG = 0mA UOK OR DOK = LOW CEN = 0 RESET TIMER CEN = HIGH OR REMOVE AND RECONNECT THE INPUT SOURCE(S) ANY STATE
STATE DIAGRAM IS FOR 10NC < TEMP < +45NC, OUTSIDE OF THIS RANGE SEE FIGURE 7
TOGGLE CEN OR REMOVE AND RECONNECT THE INPUT SOURCE(S)
PREQUAL UOK OR DOK = LOW CHG = LOW FLT = HIGH-Z DONE = HIGH-Z 0V P VBATT P 3V ICHG = ICHGMAX 10 VBATT < 2.82V, RESET TIMER VBATT > 3V, RESET TIMER TIMER > tPQ
FAULT UOK AND DOK = LOW CHG = HIGH-Z FLT = LOW DONE = HIGH-Z ICHG = 0mA
FAST-CHARGE UOK OR DOK = LOW CHG = LOW FLT = HIGH-Z DONE = HIGH-Z 3V P VBATT P 4.2V ICHG = ICHGMAX ICHG < IDONE AND VBATT = 4.2V AND THERMAL OR OUTPUT LIMIT NOT EXCEEDED RESET TIMER TOP-OFF UOK OR DOK = LOW CHG = HIGH-Z FLT = HIGH-Z DONE = HIGH-Z BATT = 4.2V ICHG = IDONE
TIMER > 15s (MAX8934A/MAX8934C /MAX8934E) TIMER > 60min (MAX8934B/MAX8934D)
VBATT < 2.82V RESET TIMER
ICHG > IDONE RESET TIMER
TIMER > tFC (TIMER SLOWED BY 2X IF ICHG < ICHGMAX/2, AND PAUSED IF ICHG < ICHGMAX/5 WHILE BATT < 4.2V)
(PQ, FC, TOP-OFF) ANY CHARGING STATE VTHM_T1 < VTHM < VTHM_T4 TIMER RESUME VTHMT1 > VTHM > VTHMT4 TIMER SUSPEND
VBATT < 4.1V RESET TIMER
TEMPERATURE SUSPEND ICHG = 0mA UOK OR DOK = PREVIOUS STATE CHG = HIGH-Z FLT = HIGH-Z DONE = HIGH-Z VTHM > VTHM_OT OVERTEMP OT = LOW VTHM < VTHM_OT
DONE UOK OR DOK = LOW CHG = HIGH-Z FLT = HIGH-Z DONE = LOW 4.1V < VBATT < 4.2V ICHG = 0mA
Figure 8. Charger State Diagram ______________________________________________________________________________________ 27
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring MAX8934A-MAX8934E
The ultra-low quiescent current LDO is always on and is preset to an output voltage of 3.3V. The LDO provides up to 30mA output current. When DC and USB are invalid and the battery is discharging, the LDO output voltage tracks VSYS as it drops below 3.3V. A 1FF ceramic capacitor connected from LDO to GND is recommended for most applications.
Always-On LDO
Table 3. Package Thermal Characteristics
28-PIN 4mm x 4mm THIN QFN SINGLE-LAYER PCB Continuous Power Dissipation BJA BJC 1666.7mW (derate 20.8mW/NC above +70NC) 48NC/W 3NC/W MULTILAYER PCB 2286mW (derate 28.6mW/NC above +70NC) 35NC/W 3NC/W
Good design minimizes ground bounce and voltage gradients in the ground plane. GND should connect to the power-ground plane at only one point to minimize the effects of power-ground currents. Battery ground should connect directly to the power-ground plane. Connect GND to the exposed pad directly under the IC. Use multiple tightly spaced vias to the ground plane under the exposed pad to help cool the IC. Position input capacitors from DC, SYS, BATT, and USB to the power-ground plane as close as possible to the IC. Keep high current traces such as those to DC, SYS, and BATT as short and wide as possible. Refer to the MAX8934 Evaluation Kit for a suitable PCB layout example.
Power Dissipation PCB Layout and Routing
Chip Information
PROCESS: BiCMOS
Pin Configuration
THMSW BATT BATT USB USB LDO
TOP VIEW
THMEN
Ordering Information
PART MAX8934BETI+ MAX8934CETI+ TEMP RANGE -40NC to +85NC -40NC to +85NC -40NC to +85NC -40NC to +85NC PIN-PACKAGE 28 Thin QFN-EP* 28 Thin QFN-EP* 28 Thin QFN-EP* 28 Thin QFN-EP*
21 CHG 22 SYS 23 SYS 24 OT 25 DOK 26 UOK 27 FLT 28 1 DONE
20
19
18
17
16
15 14 13 12 THM GND USUS ISET CT GND VL
MAX8934DETI+ MAX8934EETI+ *EP = Exposed pad.
MAX8934A- MAX8934E
*EP
+Denotes a lead(Pb)-free/RoHS-compliant package.
11 10 9 8
2 DC
3 DC
4 CEN
5 PEN1
6 PEN2
7 PSET
THIN QFN
*EXPOSED PAD
Selector Guide
SYS VOLTAGE (V) 5.3 4.35 4.35 4.35 4.35 THERMISTOR BETA 3964 3477 3964 3477 3477 TOP-OFF TIMER 15s 60min 15s 60min 15s USB INPUT CURRENT LIMIT (max) 500mA 500mA 500mA 1.5A 500mA
PART MAX8934AETI+ MAX8934BETI+ MAX8934CETI+ MAX8934DETI+ MAX8934EETI+
SAFETY REGION** 1 1 1 1 1
**For safety region 2, contact factory. For thermistor Beta = 3477, contact factory.
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Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring
Package Information
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a "+", "#", or "-" in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE 28 TQFN-EP PACKAGE CODE T2844+1 DOCUMENT NO. 21-0139
MAX8934A-MAX8934E
______________________________________________________________________________________
29
24L QFN THIN.EPS
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring MAX8934A-MAX8934E
Package Information (continued)
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a "+", "#", or "-" in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status.
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Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring
Revision History
REVISION NUMBER 0 1 REVISION DATE 2/10 3/10 Initial release Added lead temperature and tightened BATT regulation voltage specs DESCRIPTION DATE PAGES CHANGED -- 2, 4
MAX8934A-MAX8934E
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
(c)
31
2010 Maxim Integrated Products
Maxim is a registered trademark of Maxim Integrated Products, Inc.

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