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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 write-
protects 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
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.
DS1260
Smart Battery
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See Mech. Dra wings Sect ion
DS1260
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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 primar y 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 th an 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 DIAGR AM Figure 1
DS1260
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BATTERY PERFORMANCE DS1260-25
DS1260
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BATTERY PERFORMANCE DS1260-50
DS1260
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BATTERY PERFORMANCE DS1260-100
DS1260
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Table 1 PART NO. CAPACITY NOMINAL VOLTAGE
DS1260-25 250 mAH 3 volts
DS1260-50 480 mAH 3 volts
DS1260-100 960 mAH 3 volts
RESET TIMING Figure 2
INTEGRATED BATTERY BACKUP – APPLICATIONS Figure 3
DS1260
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ABSOLUTE MAXIMUM RA TINGS*
Voltage on Any Pin Relative to Ground -0.3V to +7.0V
Operating Temperature 0°C to 70°C
Storage Temperat ure -40°C to +70°C
Soldering Temperature 260°C 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 (0°C to 70°C)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Primary Power Supply VCC 4.5 5.0 5.5 V 1
Input High Voltage VIH 2.0 VCCI+0.3 V 1
Input Low Voltage VIL -0.3 +0.8 V 1
DC ELECTRICAL CHAR ACTERISTI CS (0°C to 70°C; VCCI = 4.0 to 5.5V)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Leakage Current ILO -1.0 +1.0 µA
Output Current @ 2.4V IOH -1.0 mA 1, 2
Output Current @ 0.4V IOL +4.0 mA 1, 2
Input Supply Current ICCI 5mA3
Pins 12, 13 VCCO=VCCI-0.2 ICCO 250 mA
Pin 11 PF Detect VTP 4.25 4.5 V 4
Pin 3 BF Detect VBATF 2.0 V 7
(0°C to 70°C; VCCI < VBAT)
Pin 5 Battery Voltage VBAT 3V6
Pins 12, 13 VCCO=VBAT-0.2 ICCO2 15 mA 5
Battery Leakage IBAT 100 nA 8, 9
Pin 5 Battery Output Current IBATOUT 100 µA
CAPACITANCE (tA = 25°C)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Output Capacitance CO510pF
Input Capacitance CI510pF
AC EL ECTRICAL CHARACTERISTICS (0°C to 70°C; VCCI = 4.0 to 5.5V)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
VCCI Slew Rate tF300 µs
VCCI Slew Rate tR1µs
Power-Down to PF Lo w tPF 0µs
PF High after Power-Up tREC 100 µs
DS1260
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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 25°C.
10. VCCI = +5 volts; tA = 25°C.
