Dallas Semiconductor DS1260-50, DS1260-25, DS1260-100 Datasheet
www.dalsemi.com
DS1260
Smart Battery
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
16
1
15
2
14
3
13
4
12
5
11
6
10
7
9
8
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 )
CCI
CCO
)
)
Pins 12 and 13 are RAM Supply (V
Pins 15 and 16 are +5V Supply (V
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 int erconnect and simple replacement if the energy has
been exhausted.
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DS1260
OPERATION
During normal operation V
V
(pins 12 and 13) through an internal switch at a voltage level of V
CCO
this time the power-fail signal (PF ) is held high, indicating valid primary voltage (see Figure 1).
However, if the V
falls below the level of 4.25 volts, the power-fail signal is driven low. As V
CCI
below the level of the lithium supply (V
supplies power to the uninterruptible output (V
(pins 15 and 16) is the primary energy source and power is supplied to
CCI
-0.2 volts @ 250 mA. During
CCI
CCI
= 3 volts), power is switched and the lithium energy source
BAT
CCO
) at V
-0.2 volts @ 5 mA.
BAT
falls
On power-up, as the V
supply. As the V
input rises above 4.25 volts, the power-fail signal is driven back to the hi gh level.
CCI
supply rises above 3 volts, the primary energy source, V
CCI
During normal operation, BAT (Pin 5) stays at the battery level of 3 volts, regardless of the level of V
, becomes the
CCI
CCI
.
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 V
even if V
falls below 3 volts. This feature is activated by applying a pulsed input on RST to a high
CCI
level (VIH) for 50ns minimum while primary power is valid (see Figure 2). When primary power is
removed after pulsing RST, the V
power is applied such that V
is greater than V
CCI
by the lithium energy source when V
output and BAT will go to high impedance. The next time primary
CCO
, normal operation resumes and V
BAT
again falls below 3 volts. BAT will also return to the level V
CCI
will be supplied
CCO
Figure 3 shows how the SmartBattery is used in a system application.
and BAT
CCO
BAT
BLOCK DIAGRAM Figure 1
.
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BATTERY PERFORMANCE DS1260-25
DS1260
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