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19-3263; Rev 1; 7/04
Positive High-Voltage, Hot-Swap Controllers
General Description
The MAX5933A-MAX5933F/MAX5947A/B/C fully integrated hot-swap controllers for +9V to +80V positive supply rails (MAX5947A/B/C), allow for the safe insertion and removal of circuit cards into live backplanes without causing glitches on the backplane power-supply rail. The MAX5947B is pin- and function-compatible with the LT1641-2. The other devices offer added features such as a choice of active-high or active-low power-good outputs (PWRGD/PWRGD), latched/autoretry fault management, and autoretry duty-cycle options of 3.75% or 0.94% (see the Selector Guide). The MAX5933A-MAX5933F are available with a default undervoltage lockout threshold of +31V and operate over a supply voltage range of +33V to +80V. The MAX5947A/B/C are available with a default undervoltage of +8.3V. All devices feature a programmable analog foldback current limit. If the device remains in current limit for more than a programmable time, the external n-channel MOSFET is either latched off (MAX5933A/ MAX5933C/MAX5947A) or is set to automatically restart after a timeout delay (MAX5933B/MAX5933D/MAX5933E/ MAX5933F/MAX5947B/MAX5947C). The MAX5933_ and MAX5947_ operate in the extended temperature range of -40C to +85C. These devices are available in an 8-pin SO package.
Features
Pin- and Function-Compatible with the LT1641-2 (MAX5947B) Provides Safe Hot Swap for +9V to +80V PowerSupply Range (MAX5947A/B/C) Safe Board Insertion and Removal from Live Backplanes Latched/Autoretry Management Active-Low or Active-High Power-Good Output Programmable Foldback Current Limiting High-Side Drive for an External N-Channel MOSFET Built-In Thermal Shutdown Undervoltage Lockout (UVLO) Overvoltage Protection User-Programmable Supply Voltage Power-Up Rate
MAX5933A-MAX5933F/MAX5947A/B/C
Ordering Information
PART MAX5933_ESA* MAX5947_ESA* TEMP RANGE -40C to +85C -40C to +85C PIN-PACKAGE 8 SO 8 SO
Applications
Hot Board Insertion Electronic Circuit Breakers Industrial High-Side Switch/Circuit Breakers Network Routers and Switches 24V/48V Industrial/Alarm Systems
*Insert the desired suffix from the Selector Guide into the blank to complete the part number.
Typical Application Circuit and Pin Configuration appear at end of data sheet.
Selector Guide
PART MAX5933A MAX5933B MAX5933C MAX5933D MAX5933E MAX5933F MAX5947A MAX5947B MAX5947C LATCHED FAULT PROTECTION Yes -- Yes -- -- -- Yes -- -- AUTORETRY FAULT PROTECTION -- Yes -- Yes Yes Yes -- Yes Yes PWRGD OUTPUT LOGIC High High Low Low High Low Low High Low DUTY CYCLE (%) -- 3.75 -- 3.75 0.94 0.94 -- 3.75 3.75 DEFAULT UVLO (V) 31 31 31 31 31 31 8.3 8.3 8.3 SUPPLY VOLTAGE RANGE (V) 33 to 80 33 to 80 33 to 80 33 to 80 33 to 80 33 to 80 9 to 80 9 to 80 9 to 80
________________________________________________________________ Maxim Integrated Products
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Positive High-Voltage, Hot-Swap Controllers MAX5933A-MAX5933F/MAX5947A/B/C
ABSOLUTE MAXIMUM RATINGS
(Voltages Referenced to GND) VCC .........................................................................-0.3V to +85V SENSE, FB, ON ..........................................-0.3V to (VCC + 0.3V) TIMER, PWRGD, PWRGD.......................................-0.3V to +85V GATE ......................................................................-0.3V to +95V Maximum GATE Current ....................................-50mA, +150mA Maximum Current into Any Other Pin................................50mA Continuous Power Dissipation (TA = +70C) 8-Pin SO (derate 5.9mW/C above +70C)..................470mW Operating Temperature Range ...........................-40C to +85C Maximum Junction Temperature .....................................+150C Storage Temperature Range .............................-60C to +150C Lead Temperature (soldering, 10s) .................................+300C ESD Rating (Human Body Model)......................................2000V
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
(VCC = +24V (MAX5947A/B/C), VCC = +48V (MAX5933A-MAX5933F), GND = 0V, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 1)
PARAMETER Supply Voltage Range Supply Current VCC Undervoltage Lockout VCC Undervoltage Lockout Hysteresis FB High-Voltage Threshold FB Low-Voltage Threshold FB Hysteresis FB Input Bias Current FB Threshold Line Regulation SENSE Trip Voltage (VCC - VSENSE) GATE Pullup Current GATE Pulldown Current SYMBOL VCC ICC VLKO CONDITIONS MAX5947A/B/C MAX5933A-MAX5933F VON = 3V, VCC = 80V VCC low-to-high transition MAX5947A/B/C MAX5933A-MAX5933F FB low-to-high transition FB high-to-low transition VFB = 0V VCC(MIN) VCC 80V, ON = 0V, TA = 0C to +70C VFB = 0V, TA = 0C to +70C VFB = 1V, TA = 0C to +70C Charge pump on, VGATE = 7V Any fault condition, VGATE = 2V MAX5933A-MAX5933F External N-Channel Gate Drive VGATE VGATE - VCC VCC = 10.8V to 20V, MAX5947A/B/C VCC = 20V to 80V, MAX5947A/B/C TIMER Pullup Current TIMER Pulldown Current ON Logic-High Threshold ON Logic-Low Threshold ITIMERUP ITIMERON VONH VONL VTIMER = 0V VTIMER = 1V MAX5933A-MAX5933D, MAX5947A/B/C MAX5933E/MAX5933F ON low-to-high transition ON high-to-low transition 8 39 -5 35 10 4.5 10 -24 1.5 0.37 1.280 1.221 12 47 -10 70 13.6 6.2 13.2 -80 3 0.75 1.313 1.233 1.280 1.221 -1 MAX5947A/B/C MAX5933A-MAX5933F 7.5 29.5 MIN 9 33 1.4 8.3 31 0.4 2 1.313 1.233 80 +1 0.05 17 55 -20 100 18 18.0 18 -120 4.5 1.12 1.345 1.245 V V A A V 1.345 1.245 TYP MAX 80 V 80 3.5 8.8 V 32.5 V V V mV A mV/V mV A mA mA UNITS
VLKOHYST VFBH VFBL VFBHYST IINFB VFB VSENSETRIP IGATEUP IGATEDN
2
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Positive High-Voltage, Hot-Swap Controllers
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +24V (MAX5947A/B/C), VCC = +48V (MAX5933A-MAX5933F), GND = 0V, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 1)
PARAMETER ON Hysteresis ON Input Bias Current PWRGD Leakage Current PWRGD Leakage Current PWRGD/PWRGD Output Low Voltage SENSE Input Bias Current Thermal Shutdown Thermal Shutdown Hysteresis ON Low-to-GATE Low Propagation Delay ON High-to-GATE High Propagation Delay FB Low-to-PWRGD Low Propagation Delay FB High-to-PWRGD High Propagation Delay (VCC - VSENSE) High-to-GATE Low Propagation Delay tPHLON tPLHON tPHLFB tPLHFB tPHLSENSE CGATE = 0, Figures 1, 2 CGATE = 0, Figures 1, 2 Figures 1, 3 Figures 1, 3 TA = +25C, CGATE = 0, Figures 1, 4 0.5 ISENSE SYMBOL VONHYST IINON IOH IOL VON = 0V VPWRGD = 80V VPWRGD = 80V IO = 2mA IO = 4mA VSENSE = 0V to VCC Temperature rising -1 +150 20 6 1.7 3.2 1.5 2 -1 CONDITIONS MIN TYP 80 +1 10 10 0.4 2.5 +3 MAX UNITS mV A A A V A C C s s s s s
MAX5933A-MAX5933F/MAX5947A/B/C
Note 1: All currents into the device are positive and all currents out of the device are negative. All voltages are referenced to ground, unless otherwise noted.
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Positive High-Voltage, Hot-Swap Controllers MAX5933A-MAX5933F/MAX5947A/B/C
Test Circuit and Timing Diagrams
ON
VCC 24V
FB
SENSE
1.313V FB tPLHFB PWRGD 10nF 1V
1.233V tPHLFB 1V
MAX5933_ MAX5947_
V+ = 5V PWRGD 5k GATE
GND
TIMER
Figure 1. Test Circuit
Figure 3. FB to PWRGD Timing
1.313V ON tPLHON GATE 5V
1.233V tPHLON
VCC - SENSE GATE 1V
47mV tPHLSENSE VCC
Figure 2. ON to GATE Timing
Figure 4. SENSE to GATE Timing
4
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Positive High-Voltage, Hot-Swap Controllers
Typical Operating Characteristics
(VCC = +48V, TA = +25C, unless otherwise noted.)
FB LOW-VOLTAGE THRESHOLD vs. TEMPERATURE
MAX5933 toc02
MAX5933A-MAX5933F/MAX5947A/B/C
ICC vs. VCC
MAX5933 toc01
ICC vs. TEMPERATURE
3.0 2.5 2.0 ICC (mA) 1.5 1.0 0.5 VCC = 24V (MAX5947_) VCC = 48V (MAX5933_/MAX5947_) 1.250 1.245 FB LOW-VOLTAGE THRESHOLD (V) 1.240 1.235 1.230 1.225 1.220 1.215 1.210 1.205 0 1.200 -40 -15 10 35 60 85 -40
2.4 2.1 1.8 ICC (mA) 1.5 1.2 0.9 0.6 0.3 0 33 40 48 56 VCC (V) 64 72 TA = -40C TA = +25C TA = +85C
80
-15
10
35
60
85
TEMPERATURE (C)
TEMPERATURE (C)
FB HIGH-VOLTAGE THRESHOLD vs. TEMPERATURE
MAX5933 toc04
FB HYSTERESIS vs. TEMPERATURE
MAX5933 toc05
IGATE PULLUP CURRENT vs. TEMPERATURE
-6 IGATE PULLUP CURRENT (A) -7 -8 -9 -10 -11 -12 -13
MAX5933 toc06
1.335 1.330 FB HIGH-VOLTAGE THRESHOLD (V) 1.325 1.320 1.315 1.310 1.305 1.300 1.295 1.290 1.285 1.280 -40 -15 10 35 60
0.11 0.10 FB HYSTERESIS (V) 0.09 0.08 0.07 0.06 0.05 0.04
-5
85
-40
-15
10
35
60
85
-40
-15
10
35
60
85
TEMPERATURE (C)
TEMPERATURE (C)
TEMPERATURE (C)
GATE DRIVE vs. TEMPERATURE
MAX5933 toc07
MAX5947_ GATE DRIVE vs. VCC
14 GATE DRIVE (VGATE - VCC) (V) 12 10 8 6 4 2
MAX5933 toc08
15 14 GATE DRIVE (VGATE - VCC) (V) 13 12 11 10 9 8 7 6 5 -40 -15 10 35 60 VCC = 10.8V (MAX5947_) VCC = 48V (MAX5933_/MAX5947_)
16
85
0 0 10 20 30 40 VCC (V) 50 60 70 80
TEMPERATURE (C)
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MAX5933 toc03
2.7
5
Positive High-Voltage, Hot-Swap Controllers MAX5933A-MAX5933F/MAX5947A/B/C
Typical Operating Characteristics (continued)
(VCC = +48V, TA = +25C, unless otherwise noted.)
MAX5947_ TIMER PULLUP CURRENT vs. VCC
MAX5933 toc10 MAX5933 toc11
TIMER PULLUP CURRENT vs. TEMPERATURE
MAX5933 toc09
MAX5933_ TIMER PULLUP CURRENT vs. VCC
-73 -74 TA = +25C -75 -76 -77 -78 -79 TA = 0C TA = -40C -73 -74
-60 -65 -70 -75 -80 -85 -90 -40 -15 10 35 60
TIMER PULLUP CURRENT (A)
TIMER PULLUP CURRENT (A)
TIMER PULLUP CURRENT (A)
TA = +85C
TA = +25C -75 -76 -77 -78 -79 TA = 0C
TA = +85C
TA = -40C
85
30
40
50 VCC (V)
60
70
80
0
10
20
30
40 VCC (V)
50
60
70
80
TEMPERATURE (C)
ON HIGH-VOLTAGE THRESHOLD vs. TEMPERATURE
MAX5933 toc12
ON LOW-VOLTAGE THRESHOLD vs. TEMPERATURE
MAX5933 toc13
ON HYSTERESIS vs. TEMPERATURE
MAX5933 toc14
1.343 ON HIGH-VOLTAGE THRESHOLD (V) 1.333 1.323 1.313 1.303 1.293 1.283 -40 -15 10 35 60
1.265 ON LOW-VOLTAGE THRESHOLD (V) 1.255 1.245 1.235 1.225 1.215 1.205
0.083
0.081 ON HYSTERESIS (V)
0.079
0.077
0.075
0.073 -40 -15 10 35 60 85 -40 -15 10 35 60 85 TEMPERATURE (C) TEMPERATURE (C)
85
TEMPERATURE (C)
PWRGD VOUT LOW vs. ILOAD
MAX5933 toc15
SENSE REGULATION VOLTAGE vs. VFB
SENSE REGULATION VOLTAGE (mV) 45 40 35 30 25 20 15 10 5 0
MAX5933 toc16
20 18 16 PWRGD VOUT LOW (V) 14 12 10 8 6 4 2 0 10 30 50 ILOAD (mA) 70 TA = +85C TA = +25C TA = -40C
50
90
0
0.2
0.4
0.6
0.8
1.0
VFB (V)
6
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Positive High-Voltage, Hot-Swap Controllers
Pin Description
PIN 1 NAME ON FUNCTION ON/OFF Control Input. ON is used to implement the undervoltage lockout threshold and resets the part after a fault condition for the latched-off version (MAX5933A/MAX5933C/MAX5947A, see the Detailed Description section). Power-Good Comparator Input. Connect a resistive divider from output to FB to GND to monitor the output voltage (see the Power-Good Detection section). FB is also used as a feedback for the current-limit foldback function. Open-Drain Power-Good Output. PWRGD is high (PWRGD is low) when VFB is higher than VFBH. PWRGD is low (PWRGD is high) when VFB is lower than VFBL. Ground Timing Input. Connect a capacitor from TIMER to GND to program the maximum time the part is allowed to remain in current limit (see the TIMER section). Gate-Drive Output. The high-side gate drive for the external N-channel MOSFET (see the GATE Voltage section). Current-Sense Input. Connect a sense resistor from VCC to SENSE and the drain of the external n-channel MOSFET. Power-Supply Input. Bypass VCC to GND with a 0.1F capacitor. Input voltage range is from +9V to +80V for the MAX5947A/B/C. Input voltage range is from +33V to +80V for the MAX5933A-MAX5933F.
MAX5933A-MAX5933F/MAX5947A/B/C
2
FB PWRGD/ PWRGD GND TIMER GATE SENSE VCC
3 4 5 6 7 8
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Positive High-Voltage, Hot-Swap Controllers MAX5933A-MAX5933F/MAX5947A/B/C
Functional Diagram
FB
VCC SENSE
MAX5933_ MAX5947_
VP GEN REF GEN 0.5V CHARGE PUMP AND GATE DRIVER 12mV TO 47mV
GATE
PWRGD (PWRGD)
OPEN DRAIN
1.233V
ON VCC UNDERVOLTAGE LOCKOUT
VUVLO
LOGIC VP
0.5V 80A
1.233V TIMER 3A *0.75A
( ) FOR THE MAX5933C/D/F AND THE MAX5947A/C. *FOR THE MAX5933E/MAX5933F.
GND
8
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Positive High-Voltage, Hot-Swap Controllers
Detailed Description
The MAX5933_ and MAX5947_ are fully integrated hotswap controllers for positive supply rails. The devices allow for the safe insertion and removal of circuit cards into live backplanes without causing glitches on the backplane power-supply rail. During startup, the MAX5933_ and MAX5947_ act as current regulators using an external sense resistor and a MOSFET to limit the amount of current drawn by the load. The MAX5933_ operate from a +33V to +80V supply voltage range and have a default undervoltage lockout (UVLO) set to +31V. The MAX5947_ operate from a +9V to +80V supply voltage range and have a default UVLO set to +8.3V. The UVLO threshold is adjustable using a resistive divider connected from VCC to ON to GND (see Figure 5). The MAX5933_ and MAX5947_ monitor the input voltage, the output voltage, the output current, and the die temperature. These devices feature power-good outputs (PWRGD/PWRGD) to indicate the status of the output voltage by monitoring the voltage at FB (see the PowerGood Detection section). As shown in Figure 5, a sense resistor is connected between V CC and SENSE to regulate the voltage across the sense resistor (VIN - VSENSE) to 47mV when the voltage at FB 0.5V. The current-limit threshold (VSENSETRIP) decreases linearly from 47mV to 12mV as FB decreases from 0.5V to 0V. An undervoltage fault is detected when ON goes below the threshold (VONL = 1.233V) and the voltage at GATE goes low as a result to turn off the MOSFET. ON must pass the V ONH = 1.313V threshold to turn on the MOSFET again.
MAX5933A-MAX5933F/MAX5947A/B/C
VIN 24V
RSENSE 0.025
Q1 IRF530 CL R5 10 5% D1 CMPZ5248B R6 1k 5% 6 GATE 2 R4 3.57k 1% 3 C1 10nF FB R3 59k 1% R7 24k 5%
R1 49.9k 1%
0.1F
8 VCC 1 R2 3.4k 1% 5
7 SENSE
ON
MAX5933A
TIMER PWRGD
PWRGD
C2 0.68F
GND 4
GND
Figure 5. Application Circuit _______________________________________________________________________________________ 9
Positive High-Voltage, Hot-Swap Controllers MAX5933A-MAX5933F/MAX5947A/B/C
Applications Information
Hot-Circuit Insertion
When circuit boards are inserted into a live backplane, the supply bypass capacitors on the boards draw high peak currents from the backplane power bus as they charge up. The transient currents can permanently damage the connector pins and glitch the system supply, causing other boards in the system to reset.
Short-Circuit Protection
The MAX5933_/MAX5947_ feature a programmable foldback current limit with an electronic circuit breaker that protects against short circuits or excessive supply currents. The current limit is set by placing a sense resistor between VCC (pin 8) and SENSE (pin 7). To prevent excessive power dissipation in the pass transistor and to prevent voltage spikes on the input supply during short-circuit conditions at the output, the current folds back as a function of the output voltage that is sensed at FB (Figure 7). When the voltage at FB is 0V, the current-limit circuit drives GATE to force a constant 12mV drop across the sense resistor. As the output voltage at FB increases, the voltage across the sense resistor increases until FB reaches 0.5V. At this point, the voltage across the sense resistor is held constant at 47mV. The maximum current limit is calculated as: ILIMIT = 47mV / RSENSE For a 0.025 sense resistor, the current limit is set at 1.88A and folds back to 480mA when the output is shorted to ground. The MAX5933_/MAX5947_ also feature a variable overcurrent response time. The time required to regulate Q1's drain current depends on: 1) Q1's input capacitance 2) GATE capacitor C1 and compensation resistor R6 3) The internal delay from SENSE to GATE Figure 8 shows the delay from a voltage step at SENSE until GATE voltage starts falling, as a function of overdrive.
Power-Up Sequence
The power supply on a board is controlled by placing an external n-channel MOSFET (Q1) in the power path (Figure 5). Resistor RSENSE provides current detection and capacitor C1 provides control of the GATE slew rate. Resistor R6 provides current control-loop compensation, while R5 prevents high-frequency oscillations in Q1. Resistors R1 and R2 provide undervoltage sensing. After the power pins first make contact, transistor Q1 is turned off. When the voltage at ON exceeds the turn-on threshold voltage, the voltage on V CC exceeds the undervoltage lockout threshold, and when the voltage on TIMER is less than 1.233V, transistor Q1 turns on (Figure 6). The voltage at GATE rises with a slope equal to 10A/C1 and the supply inrush current is set at: IINRUSH = CL x 10A/C1 When the voltage across the current-sense resistor RSENSE reaches VSENSETRIP, the inrush current is limited by the internal current-limit circuitry that adjusts the voltage on GATE to maintain a constant voltage across the sense resistor. Once the voltage at the output has reached its final value, as sensed by resistors R3 and R4, PWRGD goes high or PWRGD goes low.
POWER-UP WAVEFORMS
GATE 50V/div
VCC - VSENSE
47mV
ISENSE 2A/div OUTPUT 50V/div PWRGD 50V/div 0V 20ms/div 0.5V VFB
12mV
Figure 6. Power-Up Waveforms 10
Figure 7. Current-Limit Sense Voltage vs. Feedback Voltage
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Positive High-Voltage, Hot-Swap Controllers MAX5933A-MAX5933F/MAX5947A/B/C
RESPONSE TIME TO OVERCURRENT
14 12 PROPAGATION DELAY (s) 10 8 6 4 2 0 0 100 200 300 VCC - VSENSE (mV) 10ms/div TIMER 1V/div GATE 50V/div
SHORT-CIRCUIT WAVEFORMS
OUTPUT 50V/div ISENSE 1A/div
Figure 8. Response Time to Overcurrent
Figure 9. Short-Circuit Waveforms
TIMER
TIMER provides a method for programming the maximum time the device is allowed to operate in current limit. When the current-limit circuitry is not active, TIMER is pulled to GND by a 3A current source. After the current-limit circuit becomes active, an 80A pullup current source is connected to TIMER, and the voltage rises with a slope equal to 77A/CTIMER, as long as the current-limit circuit remains active. Once the desired maximum current-limit time is chosen, the capacitor value is: C(nF) = 65 x t(ms) or TLIMIT = (CTIMER/80A) x 1.233V When the current-limit circuit turns off, TIMER is discharged to GND by the 3A current source. Whenever TIMER reaches 1.233V, the internal fault latch is set. GATE is immediately pulled to GND and TIMER is pulled back to GND by the 3A current source. When TIMER falls below 0.5V, ON is pulsed low to reset the internal fault latch. The waveform in Figure 9 shows how the output latches off following a short circuit. The drop across the sense resistor is held at 12mV as the timer ramps up. Since the output did not rise, FB remains below 0.5V and the circuit latches off. For Figure 9, CT = 100nF.
Figure 10 shows an overvoltage detection circuit. When the input voltage exceeds the Zener diode's breakdown voltage, D1 turns on and starts to pull TIMER high. After TIMER is pulled higher than 1.233V, the fault latch is set and GATE is pulled to GND immediately, turning off transistor Q1 (see Figure 11). Operation is restored either by interrupting power or by pulsing ON low.
Power-Good Detection
The MAX5933_/MAX5947_ include a comparator for monitoring the output voltage. The noninverting input (FB) is compared against an internal 1.233V precision reference and exhibits 80mV hysteresis. The comparator's output (PWRGD) is open drain and capable of operating from a pullup as high as 80V. The PWRGD is similar to PWRGD with an opposite polarity (active low) output. The PWRGD (PWRGD) can be used to directly enable/disable a power module with an active-high enable input. Figure 12 shows how to use PWRGD to control an active-low enable-input power module. Signal inversion is accomplished by transistor Q2 and R7.
Supply Transient Protection
The MAX5933_/MAX5947_ are 100% tested and guaranteed to be safe from damage with supply voltages up to 80V. However, spikes above 85V may damage the device. During a short-circuit condition, the large change in currents flowing through the power-supply traces can cause inductive voltage spikes which could exceed 85V. To minimize the spikes, the power-trace parasitic inductance should be minimized by using wider traces or heavier trace plating and a 0.1F bypass capacitor placed between VCC and GND. A transient voltage suppressor (TVS) at the input can also prevent damage from voltage surges.
Undervoltage and Overvoltage Detection
ON can be used to detect an undervoltage condition at the power-supply input. ON is internally connected to an analog comparator with 80mV of hysteresis. If ON falls below its threshold voltage (1.233V), GATE is pulled low and is held low until ON is high again.
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Positive High-Voltage, Hot-Swap Controllers MAX5933A-MAX5933F/MAX5947A/B/C
RSENSE 0.025 VIN SHORT PIN R1 49.9k 1%
Q1 IRF530 CL R5 10 5% D2 CMPZ5248B R6 1k 5% 6 GATE 2 R4 3.57k 1% 3 C1 10nF FB R3 59k 1% R7 24k 5%
D1 30V 1N5256B
0.1F 8 VCC 1 7 SENSE
ON
R2 3.4k 1% C2 0.68F
MAX5933B MAX5947B
5 TIMER PWRGD
PWRGD
GND 4
GND
Figure 10. Overvoltage Detection
GATE Voltage
OVERVOLTAGE WAVEFORMS
IN 50V/div ISENSE 5A/div
GATE 50V/div TIMER 10V/div OUTPUT 50V/div 10s/div
A curve of Gate Drive vs. VCC is shown in Figure 13. GATE is clamped to a maximum voltage of 18V above the input voltage. At a minimum input-supply voltage of 33V, the minimum gate drive voltage is 10V. When the input supply voltage is higher than 20V, the gate-drive voltage is at least 10V and a standard n-channel MOSFET can be used. Using the MAX5947 in applications over a 9V to 20V range, a logic-level N-FET must be used with a proper protection Zener diode between its gate and source (see D1 in Figure 5).
Thermal Shutdown
If the MAX5933_/MAX5947_ die temperature reaches +150C, an overtemperature fault is generated. As a result, GATE goes low and turns the external MOSFET off. The MAX5933_/MAX5947_ die temperature must cool down below +130C before the overtemperature fault condition is removed.
Figure 11. Overvoltage Waveforms 12
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Positive High-Voltage, Hot-Swap Controllers MAX5933A-MAX5933F/MAX5947A/B/C
RSENSE 0.01 VIN SHORT PIN R1 294k 1%
Q1 IRF530
0.1F
R5 10 5%
D1 CMPZ5248B R6 1k 5% 6 GATE 2 R4 4.22k 1% 3 C1 10nF FB R3 143k 1% R7 47k 5% VIN+ ON/OFF VINVOUTVOUT+ VOUT
CL 220F
8 VCC 1
7 SENSE
ON
MAX5933A
R2 10.2k 1% C2 0.68F 5 TIMER PWRGD
GND 4
GND
Figure 12. Active-Low Enable Module GATE DRIVE vs. VCC
16 14 GATE DRIVE (VGATE - VCC) (V) 12 10 8 6 4 2 0 0 20 40 VCC (V) 60 80
Layout Considerations
To achieve accurate current sensing, a Kelvin connection is recommended. The minimum trace width for 1oz copper foil is 0.02in per amplifier to ensure the trace stays at a reasonable temperature. However, 0.03in. per amplifier or wider is recommended. Note that 1oz copper exhibits a sheet resistance of approximately 530/square. Small resistances add up quickly in high-current applications. To improve noise immunity, connect the resistor-divider to ON close to the device, and keep traces to V CC and GND short. A 0.1F capacitor from ON to GND also helps reject induced noise. Figure 14 shows a layout that addresses these issues. It is recommended that 2oz copper is used, particularly as the external MOSFET must be thermally coupled to the MAX5933_/MAX5947_ to ensure proper thermal-shutdown operation.
Figure 13. Gate Drive vs. Supply Voltage ______________________________________________________________________________________ 13
Positive High-Voltage, Hot-Swap Controllers MAX5933A-MAX5933F/MAX5947A/B/C
Chip Information
TRANSISTOR COUNT: 1573 PROCESS: BiCMOS
MAX5933_ MAX5947_
Pin Configuration
TOP VIEW
IRF530
ON 1 FB 2 PWRGD (PWRGD) 3
8 7
VCC SENSE GATE TIMER
MAX5933_ MAX5947_
6 5
GND 4
SO Figure 14. Recommended Layout for R1, R2, and RSENSE
( ) ONLY FOR THE MAX5933C/D/F/MAX5947A/MAX5947C.
Typical Application Circuit
RSENSE 0.01 VIN Q1 IRF530 CL R5 10 5% D1 CMPZ5248B R6 1k 5% 6 GATE 2 R4 3.57k 1% 3 C1 10nF FB R3 59k 1% R7 24k 5%
*SMBJ51A
R1 49.9k 1%
0.1F
8 VCC 1 R2 3.4k 1% 5
7 SENSE
ON
MAX5933A
TIMER PWRGD
PWRGD
C2 0.68F
GND 4
GND *DIODES, INC.
14
______________________________________________________________________________________
Positive High-Voltage, Hot-Swap Controllers
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.)
SOICN .EPS
MAX5933A-MAX5933F/MAX5947A/B/C
INCHES DIM A A1 B C e E H L MAX MIN 0.069 0.053 0.010 0.004 0.014 0.019 0.007 0.010 0.050 BSC 0.150 0.157 0.228 0.244 0.016 0.050
MILLIMETERS MAX MIN 1.35 1.75 0.10 0.25 0.35 0.49 0.19 0.25 1.27 BSC 3.80 4.00 5.80 6.20 0.40 1.27
N
E
H
VARIATIONS:
1
INCHES
MILLIMETERS MIN 4.80 8.55 9.80 MAX 5.00 8.75 10.00 N MS012 8 AA 14 AB 16 AC
TOP VIEW
DIM D D D
MIN 0.189 0.337 0.386
MAX 0.197 0.344 0.394
D C
A e B A1
0-8 L
FRONT VIEW
SIDE VIEW
PROPRIETARY INFORMATION TITLE:
PACKAGE OUTLINE, .150" SOIC
APPROVAL DOCUMENT CONTROL NO. REV.
21-0041
B
1 1
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 ____________________ 15 (c) 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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