ETC DS1259S

DS1259
Battery Manager Chip
www.dalsemi.com
FEATURES
PIN ASSIGNMENT
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
BF
BAT
RST
GND
PF
VCCO
VCCI
1
16
VCCI
VBAT
2
15
VCCI
BF
3
14
NC
NC
4
13
VCCO
BAT
5
12
VCCO
RST
6
11
PF
GND
7
10
NC
GND
8
9
NC
16-Pin DIP Package (300-mil)
See Mech. Drawings Section
PIN DESCRIPTION
NC
VBAT
NC
- No Connect
- Battery Input Connection
- Battery Fail
Output Signal
- Battery Output
- Reset Input
- Ground
- Power Fail
Output Signal
- RAM Supply
- +5V Supply
NC
1
16
VCCI
VBAT
2
15
VCCI
BF
3
14
NC
NC
4
13
VCCO
BAT
5
12
VCCO
RST
6
11
PF
GND
7
10
NC
GND
8
9
NC
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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111999
DS1259
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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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
VCCI
VIH
VIL
VBAT
BAT
MIN
2.0
-0.3
2.5
VBAT-0.1
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
PARAMETER
Pins 12, 13 VCCO=VBAT-0.2V
Battery Leakage
Pin 5 Battery Output Current
TYP
5
3
MAX
5.5
VCC+0.3
+0.8
3.7
TYP
(1.26xVBAT)
(1.26xVBAT)
VBATF
-250mV
1.5
+250mV
2.0
MIN
TYP
MAX
+250
NOTES
2.6
V
7
MAX
15
100
100
UNITS
mA
nA
µA
NOTES
5
8
+4.0
10
250
1, 2
1, 2
3
4, 6
(TA = 25°C)
SYMBOL
CIN
COUT
MIN
AC ELECTRICAL CHARACTERISTICS
PARAMETER
VCCI Slew Rate
VCCI Slew Rate
Power-Down to PF Low
PF High after Power-Up
NOTES
1
1
1
6
1
UNITS
µA
mA
mA
mA
mA
V
CAPACITANCE
PARAMETER
Input Capacitance
Output Capacitance
UNITS
V
V
V
V
V
(0°C to 70°C; VCC = 4.5 to 5.5V)
SYMBOL
ILO
IOH
IOL
ICCI
ICCO
VTP
SYMBOL
ICCO2
IBAT
IBATOUT
MIN
-1.0
-1.0
(0°C to 70°C)
SYMBOL
tF
tR
tPF
tREC
MIN
300
1
0
MAX
10
10
UNITS
pF
pF
NOTES
(0°C to 70°C; VCC = 4.0 to 5.5V)
TYP
MAX
100
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TYP
5
5
UNITS
µs
µs
µs
µs
NOTES
9
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. 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 0°C to 70°C operation.
8. Battery leakage is the internal energy consumed by the DS1259.
9. VCC = +5 volts, tA = 25°C.
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