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OBSOLETE:
LT1239
Backup Battery
Management Circuit
I
I
I
I
I
I
I
I
I
I
I
I
Micropower Operation (I
Q
= 20
µ
A)
Adjustable Regulator for Battery Charging
4.85V Regulator for Battery Regulation
Cell Voltage Equalization in 2-Cell Systems
Low-Battery Detector Protects Lithium Cells
Comparator for Automatic Power Switching
Shutdown
Output Current Sensing
Current and Thermal Limiting
Reverse Output Protection
16-Pin SO Package
Operates on 7V to 30V Input
APPLICATIONS
I
I
I
Backup Battery Management Systems for Portable
Computers
Lithium-Ion Backup Systems
NiCd Backup Systems
The LT
®
1239 is a micropower backup battery manage-
ment system for portable computers and instrumenta-
tion. It contains two regulators for regulating the battery
voltage and memory voltage and a comparator for switch-
ing between main power and backup power. The first
regulator provides a constant voltage charge for the
backup batteries and is adjustable from 3.75V up to 20V.
An equalization amplifier combined with the first regulator
provides precision charge equalization for a 2-cell
lithium-ion system. A second regulator with 4.85V output
provides a regulated backup battery voltage to the memory
when main power is lost. The second regulator also
isolates the backup battery from the main 5V supply
during normal operation when the memory is being pow-
ered by the 5V supply.
A comparator is included which provides automatic
switchover from main 5V power to backup power ensur-
ing uninterrupted power for memory and power monitor-
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
U
Lithium-Ion Backup System
INPUT 2
14
22µF
3
SHDN1
INPUT 1
10
OUT 1
REGULATOR
#1
ADJ
I
MON1
E/A (IN)
INPUT 2
GND
2
IN
LOW-BATTERY
DETECT
GND
16
1
15
7
681k
1%
8
3.4V
Li-Ion
CELL
13
5V SYSTEM
POWER
69.8k
1%
120Ω* 120Ω*
604k
1%
300pF
MAIN
BATTERY
PACK
7V TO 24V
+
E/A (OUT)
5V
IN
GND
4
GND
5
IN
REGULATOR
#2
OUT
INPUT 1
+
–
GND
OUT 2
12
MEMORY
POWER
MANAGEMENT
* REQUIRED BY SOME SAFETY AGENCIES
SEE APPLICATIONS INFORMATION
FOR INFORMATION ON
SELECTING VALUES.
LTC1239 • TA01
6
SHDN2
I
MON2
11
U
FEATURES
DESCRIPTION
+
–
U
+
22µF
3.4V
Li-Ion
CELL
1
LT1239
DESCRIPTION
ing circuitry. A low-battery detector with a 5V threshold
powers down the second regulator and the error amplifier
to limit the discharge voltage of the backup cells. This
prevents deep discharge damage to the lithium cells. Both
regulators have independent shutdown and current moni-
tor functions.
ABSOLUTE
MAXIMUM
RATINGS
Input 1 Voltage ......................................................
±30V
Input 2 Voltage ............................................. 30V, – 0.6V
Output 1 Voltage ........................................... 30V, – 0.6V
Output 2 Voltage ............................................. 6V, – 0.6V
Adjust Pin Current ................................................ 10mA
SHDN1, SHDN2 (Note 2)
Input Voltage .............................................. 6V, – 0.6V
Input Current ...................................................... 5mA
I
MON1
Voltage
(Note 3) .......................... (V
IN1
– 30V) < I
MON1
< V
IN1
I
MON2
Voltage
(Note 4) .......................... (V
IN2
– 30V) < I
MON2
< V
IN2
E/A Output Voltage (Note 5) .... – 0.6V < V
E/A(OUT)
< V
IN2
E/A Input Voltage (Note 5) .......... – 0.6V < V
E/A(IN)
< V
IN2
5V Input Voltage ............................................. 6V, – 0.6V
Operating Temperature Range ......................... 0 to 70°C
Junction Temperature Range .............................(Note 6)
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
(Note 1)
PACKAGE/ORDER INFORMATION
TOP VIEW
ADJ 1
GND 2
SHDN1 3
GND 4
GND 5
SHDN2 6
E/A (IN) 7
E/A (OUT) 8
16 OUT 1
15 I
MON1
14 INPUT 1
13 5V
IN
12 OUT 2
11 I
MON2
10 INPUT 2
9
NC
ORDER PART
NUMBER
LT1239CS
S PACKAGE
16-LEAD PLASTIC SO
T
JMAX
= 100°C,
θ
JA
= 120°C/ W
Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS
PARAMETER
Regulator 1 (Notes 7, 8)
Regulated Output Voltage (V
ADJ
= V
OUT1
)
Line Regulation
Load Regulation
V
IN1
= 4.3V, I
OUT
= 1mA, T
J
= 25°C
V
IN1
= 4.8V to 24V, I
OUT
= 1mA to 30mA
I
LOAD
= 1mA, V
IN1
= 4.3V to 30V
V
IN1
= 5V, I
LOAD
= 1mA to 30mA, T
J
= 25°C
V
IN1
= 5V, I
LOAD
= 1mA to 30mA
V
IN1
= 5V, I
LOAD
= 1mA to 50mA, T
J
= 25°C
V
IN1
= 5V, I
LOAD
= 1mA to 50mA
I
LOAD
= 1mA, T
J
= 25°C
I
LOAD
= 30mA, T
J
= 25°C
I
LOAD
= 50mA, T
J
= 25°C
I
LOAD
= 0mA, V
IN1
= 3.75V
I
LOAD
= 30mA, V
IN1
= 3.75V
I
LOAD
= 50mA, V
IN1
= 3.75V
T
J
= 25°C
q
q
q
q
q
CONDITIONS
MIN
3.700
3.650
TYP
3.750
3.750
2
– 12
– 20
– 20
– 30
0.15
0.25
0.30
20
0.80
1.35
40
MAX
3.800
3.825
10
– 25
– 50
UNITS
V
V
mV
mV
mV
mV
mV
V
V
V
µA
mA
mA
nA
Dropout Voltage (Note 9)
0.20
0.40
30
1.2
120
Ground Pin Current (Notes 10, 11)
Adjust Pin Bias Current (Note 12)
2
U
W
U
U
W W
U
W
LT1239
ELECTRICAL CHARACTERISTICS
PARAMETER
Regulator 1 (Notes 7, 8)
Shutdown Threshold
Shutdown Pin Current (Note 13)
Quiescent Current in Shutdown (Note 10)
Ripple Rejection
Current Limit
Reverse Output Current
Current Monitor Pin Output Current
V
OUT1
= Off to On
V
OUT1
= On to Off
V
SHDN1
= 0V
V
IN1
= 24V, V
SHDN1
= 0V
V
IN1
= 5V (Avg), V
RIPPLE
= 0.5V
P-P
f
RIPPLE
= 120Hz, I
LOAD
= 20mA, T
J
= 25°C
V
IN1
= 7V, V
OUT1
= 0V, T
J
= 25°C
V
OUT1
= V
OUT1(NOM)
– 100mV, T
J
= 25°C
V
OUT1
= 3.75V, V
IN1
< 3.75V
V
OUT1
= 3.75V, V
IN1
= Open Circuit
V
OUT1
= 3.75V, V
IMON1
= 0V, I
OUT1
= 1mA
V
OUT1
= 3.75V, V
IMON1
= 0V, I
OUT1
= 10mA
V
OUT1
= 3.75V, V
IMON1
= 0V, I
OUT1
= 50mA
V
IN1
= 7V, V
IN2
= 0V, V
5VIN
= 5V, I
OUT2
= 1mA
V
IN1
= 7V, V
IN2
= 0V, V
5VIN
= 5V, I
OUT2
= 30mA
V
IN1
= 7V, V
IN2
= 0V, V
5VIN
= 5V, I
OUT2
= 50mA
T
J
= 25°C
T
J
= 25°C
T
J
= 25°C
V
IN2
= 6.8V, I
OUT
= 1mA, T
J
= 25°C
I
OUT2
= 1mA, V
IN2
= 5.4V to 10V
V
IN2
= 6.8V, I
LOAD
= 1mA to 30mA, T
J
= 25°C
V
IN2
= 6.8V, I
LOAD
= 1mA to 30mA
V
IN2
= 6.8V, I
LOAD
= 1mA to 50mA, T
J
= 25°C
V
IN2
= 6.8V, I
LOAD
= 1mA to 50mA
I
LOAD
= 0mA, V
IN2
= 5.4V
I
LOAD
= 30mA, V
IN2
= 5.4V
I
LOAD
= 50mA, V
IN2
= 5.4V
V
OUT2
= Off to On
V
OUT2
= On to Off
V
SHDN2
= 0V
V
IN2
= 6.4V (Avg), V
RIPPLE
= 0.5V
P-P
f
RIPPLE
= 120Hz, I
LOAD
= 20mA, T
J
= 25°C
V
IN2
= 6.8V, V
OUT2
= 0V, T
J
25°C
V
OUT2
= V
OUT2(NOM)
– 100mV, T
J
= 25°C
V
OUT2
= 4.85V, V
IN2
< 4.85V
V
OUT2
= 4.85V, V
IN2
= Open Circuit
V
OUT2
= 6.8V, V
IMON2
= 0V, I
OUT2
= 1mA
V
OUT2
= 6.8V, V
IMON2
= 0V, I
OUT2
= 10mA
V
OUT2
= 6.8V, V
IMON2
= 0V, I
OUT2
= 50mA
V
E/A(IN)
= 3.4V, V
IN2
= 6.8V
q
q
q
q
q
q
q
q
q
q
q
q
CONDITIONS
MIN
TYP
1.20
0.75
2
10
MAX
2.8
4
16
UNITS
V
V
µA
µA
dB
mA
mA
0.25
50
30
40
59
50
70
6
6
12
12
50
µA
µA
µA
µA
µA
mV
mV
mV
V
V
V
38
4.6
44
215
12
110
135
Comparator
Output Saturation Voltage (V
5VIN
– V
OUT2
)
q
q
q
40
150
220
5.15
Low-Battery Detector
Turn-Off Threshold
Turn-On Threshold
Hysteresis
Regulator 2
Regulated Output Voltage
Output Voltage Temperature Coefficient
Line Regulation
Load Regulation
4.775
4.850
– 0.5
2
– 12
– 20
– 20
– 30
16
0.80
1.35
0.25
1.20
0.75
1.7
50
30
40
58
50
70
6
6
35
4.7
41
210
3
12
12
47
5
– 25
– 50
4.925
V
mV/°C
mV
mV
mV
mV
mV
µA
mA
mA
V
V
µA
dB
mA
mA
µA
µA
µA
µA
µA
nA
4.85
0.2
5.00
5.3
0.3
Ground Pin Current
q
q
q
q
q
q
25
1.2
2.8
4
Shutdown Threshold
Shutdown Pin Current
Ripple Rejection
Current Limit
Reverse Output Current
Current Monitor Pin Output Current
Error Amplifier
Bias Current
q
20
3
LT1239
ELECTRICAL CHARACTERISTICS
PARAMETER
Offset Voltage
Output Current Sourcing
Sinking
Quiescent Current
V
IN2
= 6.8V, V
E/A(IN)
= 3.4V, T
J
= 25°C
V
IN2
= 6.8V, V
E/A(IN)
= 3.4V, T
J
= 25°C
V
IN2
= 6.8V, 5V
IN
= 0V, V
E/A(IN)
= 3.4V
V
IN2
= 6.8V, 5V
IN
= 0V, V
E/A(IN)
= 3.4V, V
PIN6
= 0V
V
IN2
= 4.8V, 5V
IN
= 0V, V
E/A(IN)
= 2.4V
q
q
q
CONDITIONS
q
MIN
3
3
TYP
0
5
5
20
8
3
MAX
15
UNITS
mV
mA
mA
Regulator 2, Low Battery Detector and Error Amplifier
30
12
6
µA
µA
µA
The
q
denotes specifications which apply over the full operating
temperature range.
Note 1:
All voltages are with respect to the ground pins of the device
(pins 2, 4, 5) unless otherwise specified.
Note 2:
The shutdown pin input voltage rating is required for a low
impedance source. Internal protection devices connected to the shutdown
pin will turn on and clamp the pin to approximately 7V or – 0.6V. This
range allows the use of 5V logic devices to drive the pin directly. For high
impedance sources or logic running on supply voltages greater than 5.5V,
the maximum current driven into the shutdown pin must be limited to
5mA.
Note 3:
The current monitor pin for regulator 1 (pin 15) can be pulled 30V
below the input pin (pin 14). The current monitor pin must not be pulled
above the input pin.
Note 4:
The current monitor pin for regulator 2 (pin 11) can be pulled 30V
below the input pin (pin 10). The current monitor pin must not be pulled
above the input pin.
Note 5:
E/A (OUT) pin should not be pulled below ground or above
the voltage at Input 2.
Note 6:
The device is specified to an operating temperature range of 0°C to
70°C. The device is guaranteed to be functional up to the thermal
shutdown temperature. The thermal shutdown temperature for this device
is approximately 100°C.
Note 7:
Operating conditions are limited by maximum junction
temperature. The regulated output specification will not apply for all
possible combinations of input voltage and output current. When
operating at maximum output current, the input voltage range must be
limited. When operating at maximum input voltage, the output current
range must be limited.
Note 8:
Regulator 1 of the LT1239 is tested and specified with the adjust
pin (pin 1) tied to the output pin (pin 16). See Applications Information.
Note 9:
Dropout voltage is the minimum input/output voltage required to
maintain regulation at the specified output current. In dropout, the output
voltage measured at the package pins will be equal to (V
IN
– V
DROPOUT
).
Note 10:
The quiescent current of the comparator is included in the
ground pin current and quiescent current specifications for regulator 1.
The comparator output is turned off (pin 13 = 0V, pin 12 = 5V) during
these tests.
Note 11:
Ground pin current for regulator 1 is tested with V
IN
= V
OUT
(nominal) and a current source load. This means that the device is tested
in it’s dropout region. Ground pin current will decrease slightly at higher
input voltages.
Note 12:
Adjust pin current flows into the adjust pin.
Note 13:
Shutdown pin current at V
SHDN
= 0V flows out of
the shutdown pin.
Note 14:
6.8V is the nominal voltage of two lithium-ion cells.
TYPICAL PERFORMANCE CHARACTERISTICS
Low-Battery Detector Thresholds
vs Temperature
LOW-BATTERY DETECTOR THRESHOLD (V)
5.60
5.50
5.40
START-UP THRESHOLD
5.30
5.20
5.10
SHUTDOWN THRESHOLD
5.00
4.90
–50
4.975
REGULATOR 2 OUTPUT VOLTAGE (V)
4.900
4.875
4.850
4.825
4.800
4.775
4.750
4.725
–50
–25
25
50
0
TEMPERATURE (°C)
75
100
ADJUST PIN VOLTAGE (V)
–25
50
25
0
TEMPERATURE (°C)
4
U W
75
LT1239 • TPC01
Regulator 2 Output Voltage vs
Temperature
3.80
3.79
3.78
3.77
3.76
3.75
3.74
3.73
3.72
3.71
4.950
4.925
Regulator 1 Adjust Pin Voltage vs
Temperature
100
3.70
–50
–25
25
50
0
TEMPERATURE (°C)
75
100
LT1239 • TPC02
LT1239 • TPC03
LT1239
TYPICAL PERFORMANCE CHARACTERISTICS
Regulator 2 I
MON2
Current vs
Output Current
250
V
IN2
= 6.8V
V
IMON2
= 0V
200
QUIESCENT CURRENT (µA)
I
MON2
CURRENT (µA)
I
MON1
CURRENT (µA)
150
100
50
0
0
10
30
40
20
OUTPUT CURRENT (mA)
50
Comparator Output Saturation
Voltage vs Output Current
400
OUTPUT SATURATION VOLTAGE (mV)
20
18
350
300
250
200
150
100
50
0
0
10 20
30 40 50 60 70 80 90 100
OUTPUT CURRENT (mA)
LT1239 • TPC07
REVERSE OUTPUT CURRENT (µA)
16
14
12
10
8
6
4
2
0
0
1
2
3 4 5 6 7 8
OUTPUT VOLTAGE (V)
9
10
V
IN1
= 0V
ADJ (PIN 1) = V
OUT
(PIN 16)
REVERSE OUTPUT CURRENT (µA)
Shutdown Pin Threshold
2.0
1.8
SHUTDOWN PIN THRESHOLD (V)
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
–50 –25
(OFF-TO-ON)
I
LOAD
= 1mA
QUIESCENT CURRENT (µA)
1.6
50
0
75
25
TEMPERATURE (°C)
U W
LT1239 • TPC04
Regulator 1 I
MON
Current vs
Output Current
250
V
IMON1
= 0V
200
V
IN1
= 5V
V
OUT1
= 3.75V
V
IN1
= 24V
V
OUT1
= 6.8V
40
35
30
25
20
15
10
5
0
0
10
30
40
20
OUTPUT CURRENT (mA)
50
0
Regulator 1, Comparator Quiescent
Current vs Input Voltage, Pin 14
V
ADJ
(PIN 1) = V
OUT
(PIN 16)
150
100
V
IN1
= 5V
V
OUT1
= 3.75V
50
V
PIN3
= 0V
(REGULATOR 1 IN SHUTDOWN)
0
5
INPUT VOLTAGE, PIN 14 (V)
10
LT1239 • TPC06
LT1239 • TPC05
Regulator 1 Reverse Output
Current vs Output Voltage
20
18
16
14
12
10
8
6
4
2
0
Regulator 2 Reverse Output
Current vs Output Voltage
0
1
2
3 4 5 6 7 8
OUTPUT VOLTAGE (V)
9
10
LT1239 • TPC08
LT1239 • TPC09
Regulator 2, Error Amp, Low-
Battery Detector Quiescent Current
30
25
20
15
10
5
0
V
SHDN2
= 0V
(REGULATOR 2
IN SHUTDOWN)
V
SHDN2
= OPEN CIRCUIT
(OFF-TO-ON)
I
LOAD
= 30mA
(ON-TO-OFF)
I
LOAD
= 1mA
100
125
0
1
2 3 4 5 6 7 8
INPUT 2 VOLTAGE, PIN 10 (V)
9
10
LT1239 • TPC10
LT1239 • TPC11
5
测试/测量
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