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DS1260 Smart Battery
www.dalsemi.com
FEATURES
Encapsulated lithium energy cell with shelf life beyond 10 years Available with energy capacities of 250, 500, and 1,000 mAH @ 3 volts Plugs into a standard 16-pin DIP socket Lithium cell electrically disconnects from exposed pins upon command Battery isolation ensures full capacity after shipping and handling Lithium cell automatically reconnects when VCC is applied Recessed pins prevent bending VCC fail signal interrupts processor or writeprotects memory Exhausted energy cell warning signal Low profile permits mounting on 0.5-inch printed circuit board centers Mates directly with DS1212 Nonvolatile Controller to back up 16 SRAMs Uninterruptible supply for CMOS and portable devices
PIN ASSIGNMENT
1 2 3 4 5 6 7 8
16 15 14 13 12 11 10 9
See Mech. Drawings Section
PIN DESCRIPTION
Pins 1, 2, 4, 7, 9, 10 and 14 are No-Connects Pin 3 is Battery Fail ( BF ) Pin 5 is Battery Out (BAT) Pin 6 is RESET (RST) Input Pin 8 is Ground Pin 11 is Power Fail ( PF ) Pins 12 and 13 are RAM Supply (VCCO) Pins 15 and 16 are +5V Supply (VCCI)
DESCRIPTION
The DS1260 SmartBattery is a low-cost, backup energy supply for portable and nonvolatile electronic equipment. A lithium energy source of up to 1 amp hour can supply power to CMOS electronic circuits when primary power is lost through an intelligent and efficient switch. When power is supplied from the lithium power source, the power fail signal is held low to warn electronic (RESET) circuits of the power status. Energy loss during shipping and handling is avoided by pulsing RESET, thereby causing the backup energy source to be isolated from the exposed pins. The DS1260 can be plugged into a standard 16-pin, low-cost DIP socket, allowing for proven interconnect and simple replacement if the energy has been exhausted. 1 of 8 111999
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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 @ 250 mA. During this time the power-fail signal ( PF ) is held high, indicating valid primary voltage (see Figure 1). However, if the VCCI falls below the level of 4.25 volts, the power-fail signal is driven low. As VCCI falls below the level of the lithium supply (VBAT = 3 volts), power is switched and the lithium energy source supplies power to the uninterruptible output (VCCO) at VBAT-0.2 volts @ 5 mA. On power-up, as the VCCI supply rises above 3 volts, the primary energy source, VCCI, becomes the supply. As the VCCI input rises above 4.25 volts, the power-fail signal is driven back to the high level. During normal operation, BAT (Pin 5) stays at the battery level of 3 volts, 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 (VOH), provided that the lithium energy source is greater than 2 volts. If the lithium energy source should decrease to below 2 volts, the BF signal is driven low (VOL), indicating an exhausted lithium battery. The BF signal is always low when power is being supplied by the lithium energy source.
RESET
The reset input can be used to prevent the lithium energy source from supplying power to VCCO and BAT even if VCCI falls below 3 volts. This feature is activated by applying a pulsed input on RST to a high level (VIH) 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 lithium energy source when VCCI again falls below 3 volts. BAT will also return to the level VBAT. Figure 3 shows how the SmartBattery is used in a system application.
BLOCK DIAGRAM Figure 1
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BATTERY PERFORMANCE DS1260-25
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BATTERY PERFORMANCE DS1260-50
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BATTERY PERFORMANCE DS1260-100
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Table 1 PART NO. DS1260-25 DS1260-50 DS1260-100 CAPACITY 250 mAH 480 mAH 960 mAH NOMINAL VOLTAGE 3 volts 3 volts 3 volts
RESET TIMING Figure 2
INTEGRATED BATTERY BACKUP - APPLICATIONS 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 -40C to +70C 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 SYMBOL VCC VIH VIL MIN 4.5 2.0 -0.3 TYP 5.0 MAX 5.5 VCCI+0.3 +0.8
(0C to 70C)
UNITS V V V NOTES 1 1 1
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 SYMBOL ILO IOH IOL ICCI ICCO VTP VBATF MIN -1.0 -1.0
(0C to 70C; VCCI = 4.0 to 5.5V)
TYP MAX +1.0 +4.0 5 250 4.5 UNITS A mA mA mA mA V V NOTES 1, 2 1, 2 3 4 7
4.25 2.0
(0C to 70C; VCCI < VBAT)
Pin 5 Battery Voltage Pins 12, 13 VCCO=VBAT-0.2 Battery Leakage Pin 5 Battery Output Current VBAT ICCO2 IBAT IBATOUT 3 15 100 100 V mA nA A 6 5 8, 9
CAPACITANCE
PARAMETER Output Capacitance Input Capacitance SYMBOL CO CI 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; VCCI = 4.0 to 5.5V)
TYP MAX UNITS s s s s NOTES
100
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POWER-DOWN/POWER-UP CONDITION
WARNING:
Under no circumstances are negative undershoots, of any amplitude, allowed when device is in battery backup mode. Water washing for flux removal may discharge internal lithium source as exposed voltage pins are present.
NOTES:
1. 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. Sustained ICCO2 currents above 1 mA cause a significant drop in battery voltage. 6. VBAT is the internal lithium energy source voltage. 7. VBATF is the point that BF is driven low. 8. Battery leakage is the internal energy consumed by the DS1260. 9. Storage loss is less than 1% per year at 25C. 10. VCCI = +5 volts; tA = 25C.
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