1
LT1120A
I
20
μ
A Supply Current
I
8-Lead SOIC
I
125mA Output Current
I
2.5V Reference
I
Reference Output Sources 4mA and Sinks 4mA
I
Open Collector
I
Comparator Sinks 10mA
I
Logic Shutdown
I
0.2V Dropout Voltage
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Thermal Limiting
APPLICATIO
S
U
The LT1120A is a combination micropower positive regu-
lator and free collector comparator on a single monolithic
chip. With only 20
μ
A supply current, the LT1120A can
supply over 125mA of output current. Input voltage range
is from 4.5V to 36V and dropout voltage is 0.6V at 125mA.
Dropout voltage decreases with lower load currents. Also
included on the chip is a class B output 2.5V reference that
can either source or sink current. This allows it to be used
as a supply splitter or auxiliary output. A shutdown pin
allows logic shutdown of the output.
The comparator can be used for system or battery moni-
toring. For example, the comparator can be used to warn
of low system voltage. Frequency compensation of the
comparator for amplifier applications can be obtained by
adding external output capacitance.
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Battery Systems
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Battery Backup System
I
Portable Terminals
I
Portable Instruments
I
Memory Keep Alive
Micropower Regulator with
Comparator and Shutdown
FEATURES
DESCRIPTIO
N
U
TYPICAL APPLICATIO
N
U
Dropout Voltage and Supply Current
5V Regulator
1120A TA01
V
IN
> 5.2V
I
Q
= 20
μ
A
10
μ
F
1M
SHUTDOWN
1
3
5
4
2
0.001
μ
F
25
μ
F
1M
5V
LT1120A
V
OUT
V
IN
GNDFB
+
+
OUTPUT CURRENT (mA)
0.1
0.01
D
1.00
1
1000
1120A TA02
10
0.10
100
0.1
S
10
1