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DS1259 Battery Manager Chip
www.dalsemi.com
FEATURES
Facilitates uninterruptible power Uses battery only when primary VCC is not available Low forward voltage drop Power fail signal interrupts processor or write protects memory Consumes less than 100 nA of battery current Low battery warning signal Battery can be electrically disconnected upon command Battery will automatically reconnect when VCC is applied Mates directly with DS1212 Nonvolatile Controller x 16 Chip to back up 16 RAMs Optional 16-pin SOIC surface-mount package
PIN ASSIGNMENT
NC VBAT BF NC BAT RST GND GND 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 VCCI VCCI NC VCCO VCCO PF NC NC
16-Pin DIP Package (300-mil) See Mech. Drawings Section
PIN DESCRIPTION
NC VBAT
BF
NC VBAT BF NC BAT RST GND GND
1 2 3 4 5 6 7 8
16 15 14 13 12 11 10 9
VCCI VCCI NC VCCO VCCO PF NC NC
BAT RST GND
PF
VCCO VCCI
- No Connect - Battery Input Connection - Battery Fail Output Signal - Battery Output - Reset Input - Ground - Power Fail Output Signal - RAM Supply - +5V Supply
16-Pin SOIC Package (300-mil) See Mech. Drawings Section
DESCRIPTION
The DS1259 Battery Manager Chip is a low-cost battery management system for portable and nonvolatile electronic equipment. A battery connected to the battery input pin supplies power to CMOS electronic circuits when primary power is lost through an efficient switch via the VCCO pins. When power is supplied from the battery, the power-fail signal is active to warn electronic reset circuits of the power status. Energy loss during shipping and handling is avoided by pulsing reset, thereby causing the battery to be isolated from other elements in the circuits.
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OPERATION
During normal operation, VCCI (Pins 15 and 16) is the primary energy source and power is supplied to VCCO (Pins 12 and 13) through an internal switch at a voltage level of VCCI-0.2 volts at 250 mA. During this time the power-fail signal ( PF ) is held high, indicating valid VCCI voltage (see Figure 1). However, if the VCCI falls below the trip point (VTP), a level of 1.26 times the battery level (VBAT), the power-fail signal is driven low. As VCCI falls below the battery level, power is switched from VCCI to VBAT and the battery supplies power to the uninterruptible output (VCCO) at VBAT-0.2 volts at 15 mA. On power-up, as the VCCI supply rises above the battery, the primary energy source, VCCI, becomes the supply. As VCCI rises above the trip point (VTP), the power fail signal is driven back to the high level. During normal operation, BAT (Pin 5) stays at the battery level regardless of the level of VCCI.
BATTERY FAIL
When power is being supplied from the primary energy source, BF (Pin 3) is held at a high level, provided that the attached battery (VBAT) is greater than 2 volts. If the battery level should decrease to below 2 volts, the BF signal is driven low, indicating a low battery. The BF signal is always low when the PF signal is low.
RESET
The reset input can be used to prevent the battery from supplying power to VCCO and BAT even if VCCI falls below the level of the battery. This feature is activated by applying a pulsed input on RST to high level for 50ns minimum while primary power is valid (see Figure 2). When primary power is removed after pulsing RST, the VCCO output and BAT will go to high impedance. The next time primary power is applied such that VCCI is greater than VBAT, normal operation resumes and VCCO will be supplied by the battery or VCCI. The BAT output will also return to the level of the battery. Figure 3 shows the DS1259 in a typical application.
BLOCK DIAGRAM Figure 1
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RESET TIMING Figure 2
TYPICAL APPLICATION Figure 3
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ABSOLUTE MAXIMUM RATINGS*
Voltage on Any Pin Relative to Ground Operating Temperature Storage Temperature Soldering Temperature * -0.3V to +7.0V 0C to 70C -55C to +125C 260C for 10 seconds
This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability.
RECOMMENDED DC OPERATING CONDITIONS
PARAMETER Primary Power Supply Input High Voltage Input Low Voltage Battery Voltage Pin 2 Battery Output Pin 5 SYMBOL VCCI VIH VIL VBAT BAT MIN 2.0 -0.3 2.5 VBAT-0.1 TYP 5 MAX 5.5 VCC+0.3 +0.8 3.7
(0C to 70C)
UNITS V V V V V NOTES 1 1 1 6 1
3
DC ELECTRICAL CHARACTERISTICS
PARAMETER Leakage Current Output Current @ 2.4V Output Current @ 0.4V Input Supply Current Pins 12, 13 VCCO=VCCI-0.2 Pin 11 PF Detect Pin 3 BF Detect PARAMETER Pins 12, 13 VCCO=VBAT-0.2V Battery Leakage Pin 5 Battery Output Current SYMBOL ILO IOH IOL ICCI ICCO VTP VBATF SYMBOL ICCO2 IBAT IBATOUT MIN -1.0 -1.0
(0C to 70C; VCC = 4.5 to 5.5V)
TYP MAX +250 +4.0 10 250 UNITS A mA mA mA mA V V UNITS mA nA A NOTES 1, 2 1, 2 3 4, 6 7 NOTES 5 8
(1.26xVBAT)
(1.26xVBAT)
-250mV 1.5 MIN
+250mV 2.0 TYP
2.6 MAX 15 100 100
CAPACITANCE
PARAMETER Input Capacitance Output Capacitance SYMBOL CIN COUT MIN TYP 5 5 MAX 10 10
(TA = 25C)
UNITS pF pF NOTES
AC ELECTRICAL CHARACTERISTICS
PARAMETER VCCI Slew Rate VCCI Slew Rate Power-Down to PF Low PF High after Power-Up SYMBOL tF tR tPF tREC MIN 300 1 0
(0C to 70C; VCC = 4.0 to 5.5V)
TYP MAX UNITS s s s s NOTES
100
9
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POWER-DOWN/POWER-UP CONDITION
NOTES:
1. All voltages are referenced to ground. 2. Load capacity is 50 pF. 3. Measured with Pins 11, 12, 13, and 3 open. 4. VTP is the point that PF is driven low. 5. ICCO2 may be limited by the capability of the battery. 6. Trip point voltage for power-fail detect: VTP = 1.26 x VBAT 250 mV For 5% operation: VBAT = 3.7V max. For 10% operation: VBAT = 3.5V max. 7. VBATF is the point that BF is driven low. These limits are for 0C to 70C operation. 8. Battery leakage is the internal energy consumed by the DS1259. 9. VCC = +5 volts, tA = 25C.
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