DS1259
Battery Manager Chip
www.dalsemi.com
FEATURES
Facilitates uninterruptible power
Uses battery only when primary V
CC
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
V
CC
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
V
BAT
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
V
CCO
V
CCI
- 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 V
CCO
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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111999
DS1259
OPERATION
During normal operation, V
CCI
(Pins 15 and 16) is the primary energy source and power is supplied to
V
CCO
(Pins 12 and 13) through an internal switch at a voltage level of V
CCI
-0.2 volts at 250 mA. During
this time the power-fail signal (
PF
) is held high, indicating valid V
CCI
voltage (see Figure 1). However, if
the V
CCI
falls below the trip point (V
TP
), a level of 1.26 times the battery level (V
BAT
), the power-fail
signal is driven low. As V
CCI
falls below the battery level, power is switched from V
CCI
to V
BAT
and the
battery supplies power to the uninterruptible output (V
CCO
) at V
BAT
-0.2 volts at 15 mA.
On power-up, as the V
CCI
supply rises above the battery, the primary energy source, V
CCI
, becomes the
supply. As V
CCI
rises above the trip point (V
TP
), 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 V
CCI
.
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 (V
BAT
) 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 V
CCO
and BAT even if V
CCI
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 V
CCO
output and BAT will go to high impedance. The next time primary power is
applied such that V
CCI
is greater than V
BAT
, normal operation resumes and V
CCO
will be supplied by the
battery or V
CCI
. 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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DS1259
RESET TIMING
Figure 2
TYPICAL APPLICATION
Figure 3
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DS1259
ABSOLUTE MAXIMUM RATINGS*
Voltage on Any Pin Relative to Ground
Operating Temperature
Storage Temperature
Soldering Temperature
*
-0.3V to +7.0V
0°C to 70°C
-55°C to +125°C
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
PARAMETER
Primary Power Supply
Input High Voltage
Input Low Voltage
Battery Voltage Pin 2
Battery Output Pin 5
SYMBOL
V
CCI
V
IH
V
IL
V
BAT
BAT
MIN
2.0
-0.3
2.5
V
BAT
-0.1
TYP
5
MAX
5.5
V
CC
+0.3
+0.8
3.7
(0°C to 70°C)
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 V
CCO
=V
CCI
-0.2
Pin 11
PF
Detect
Pin 3
BF
Detect
PARAMETER
Pins 12, 13 V
CCO
=V
BAT
-0.2V
Battery Leakage
Pin 5 Battery Output Current
SYMBOL
I
LO
I
OH
I
OL
I
CCI
I
CCO
V
TP
V
BATF
SYMBOL
I
CCO2
I
BAT
I
BATOUT
MIN
-1.0
-1.0
(0°C to 70°C; V
CC
= 4.5 to 5.5V)
TYP
MAX
+250
+4.0
10
250
UNITS
µA
mA
mA
mA
mA
V
V
UNITS
mA
nA
µA
NOTES
1, 2
1, 2
3
4, 6
7
NOTES
5
8
(1.26xV
BAT
)
(1.26xV
BAT
)
-250mV
1.5
MIN
+250mV
2.0
TYP
2.6
MAX
15
100
100
CAPACITANCE
PARAMETER
Input Capacitance
Output Capacitance
SYMBOL
C
IN
C
OUT
MIN
TYP
5
5
MAX
10
10
(T
A
= 25°C)
UNITS
pF
pF
NOTES
AC ELECTRICAL CHARACTERISTICS
PARAMETER
V
CCI
Slew Rate
V
CCI
Slew Rate
Power-Down to
PF
Low
PF
High after Power-Up
SYMBOL
t
F
t
R
t
PF
t
REC
MIN
300
1
0
(0°C to 70°C; V
CC
= 4.0 to 5.5V)
TYP
MAX
UNITS
µs
µs
µs
µs
NOTES
100
9
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DS1259
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. V
TP
is the point that
PF
is driven low.
5. I
CCO2
may be limited by the capability of the battery.
6. Trip point voltage for power-fail detect:
V
TP
= 1.26 x V
BAT
± 250 mV
For 5% operation: V
BAT
= 3.7V max.
For 10% operation: V
BAT
= 3.5V max.
7. V
BATF
is the point that
BF
is driven low. These limits are for 0°C to 70°C operation.
8. Battery leakage is the internal energy consumed by the DS1259.
9. V
CC
= +5 volts, t
A
= 25°C.
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