LT1120
Micropower Regulator with
Comparator and Shutdown
FEATURES
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DESCRIPTIO
40μA Supply Current
125mA Output Current
2.5V Reference Voltage
Reference Output Sources 2mA and Sinks 2mA
Open Collector Comparator Sinks 10mA
Logic Shutdown
0.2V Dropout Voltage
Thermal Limiting
Available in 8-Lead DIP and SO Packages
The LT
®
1120 is a combination micropower positive regu-
lator and free collector comparator on a single monolithic
chip. With only 40μA supply current, the LT1120 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. 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.
The 2.5V reference will source or sink current. This allows
it to be used as a supply splitter or auxiliary output.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
APPLICATIO S
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Battery Systems
Battery-Backup System
Portable Terminals
Portable Instruments
Memory Keep-Alive
TYPICAL APPLICATIO
Dropout Voltage and Supply Current
1.00
10
5V Regulator
SUPPLY CURRENT (mA)
V
IN
> 5.2V
I
Q
= 40μA
5
V
IN
LT1120
10μF
SHDN
3
SHUTDOWN
FB
GND
1
2
1M
V
OUT
4
0.001μF
1M
5V
DROPOUT VOLTAGE (V)
+
+
25μF
0.10
1120 TA01
0.01
0.1
U
1
10
100
1
OUTPUT CURRENT (mA)
0.1
1000
1120 TA02
U
U
1120fd
1
LT1120
ABSOLUTE
AXI U RATI GS
Input Voltage ........................................................... 36V
NPN Collector Voltage ............................................. 36V
Output Short-Circuit Duration .......................... Indefinite
Power Dissipation ............................... Internally Limited
PACKAGE/ORDER I FOR ATIO
TOP VIEW
GND 1
FB 2
SHDN 3
V
OUT
4
8
7
6
5
–INPUT
COMPOUT
REF
V
IN
ORDER PART
NUMBER
LT1120CN8
LT1120CS8
LT1120IN8
LT1120IS8
S8 PART MARKING
1120
1120I
ORDER PART
NUMBER
LT1120CJ8
GND 1
FB 2
SHDN 3
S8 PACKAGE
N8 PACKAGE
8-LEAD PLASTIC SO
8-LEAD PDIP
T
JMAX
= 110°C,
θ
JA
= 130°C/W (N)
T
JMAX
= 110°C,
θ
JA
= 150°C/W (S)
J8 PACKAGE
8-LEAD CERDIP
T
JMAX
= 150°C,
θ
JA
= 100°C/W (J)
OBSOLETE PACKAGES
Consider the N8 and S8 Packages for Alternate Source
Consult LTC Marketing for parts specified with wider operating temperature ranges.
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. T
j
= 25°C.
PARAMETER
Reference
Reference Voltage
Line Regulation
Load Regulation
Output Source Current
Output Sink Current
Temperature Stability
Regulator
Supply Current
V
IN
= 6V, I
OUT
≤
100μA
V
IN
= 36V, I
OUT
≤
100μA
V
IN
= 12V, I
OUT
= 125mA
(V
IN
– V
OUT
)
≥
1V, V
IN
≥
6V
(V
IN
– V
OUT
)
≥
1V, V
IN
≥
6V
6V
≤
V
IN
≤
36V
I
OUT
= 100μA
I
OUT
= 125mA
125
0.2
0.01
0.02
0.4
0.5
0.015
0.05
0.65
45
75
11
80
100
20
μA
μA
mA
mA
%
%/V
V
V
1120fd
ELECTRICAL CHARACTERISTICS
CONDITIONS
4.5V
≤
V
IN
≤
36V
4.5V
≤
V
IN
≤
36V
–2mA
≤
I
REF
≤
2mA, V
IN
= 12V
V
IN
= 5V
V
IN
= 5V
2
2
Output Current
Load Regulation
Line Regulation
Dropout Voltage
2
U
U
W
W W
U
W
(Note 1)
Operating Temperature Range
LT1120C ................................................ 0°C to 100°C
LT1120I ................................................ – 40 to 100°C
Storage Temperature Range ................. – 65°C to 150°C
TOP VIEW
–INPUT
8
7 COMPOUT
6 REF
5 V
IN
ORDER PART
NUMBER
LT1120CH
4
V
OUT
H PACKAGE
8-LEAD TO-5 METAL CAN
T
JMAX
= 150°C,
θ
JA
= 150°C/W,
θ
JC
= 45°C/W
MIN
2.46
TYP
2.50
0.01
0.3
4
4
1
MAX
2.54
0.015
0.6
UNITS
V
%/V
%
mA
mA
%
LT1120
The
●
denotes the specifications which apply over the full
operating temperature range, otherwise specifications are at T
A
= 25°C. T
j
= 25°C.
PARAMETER
Feedback Sense Voltage
Shutdown Pin Voltage
V
OUT
≤
0.5V
Shutdown Pin Current
Feedback Bias Current
Minimum Load Current
Short-Circuit Current
Comparator
Offset Voltage
Bias Current
Gain
Power Supply Rejection
Output Sink Current
Saturation Voltage
Input Voltage Range
Response Time
Leakage Current
V
IN
= 36V
V
IN
= 36V (Note 2)
ΔV
OUT
= 29V, R
L
= 20k
4.5V
≤
V
S
≤
36V
V
IN
= 4.5V
I
OUT
= 1mA
0
5
2
2000
80
10
3
15
10000
96
18
0.4
0.6
V
IN
– 1
7
40
mV
nA
V/V
dB
mA
V
V
μs
μA
V
IN
= 36V
V
IN
= 36V
V
IN
= 1.4V
CONDITIONS
V
IN
= 12V
Normal
Shutdown
2.2
1.4
25
15
1
300
40
5
400
MIN
2.44
TYP
2.5
MAX
2.56
0.4
UNITS
V
V
V
μA
nA
μA
mA
ELECTRICAL CHARACTERISTICS
The
●
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T
A
= 25°C.
PARAMETER
Reference
Reference Voltage
Line Regulation
Load Regulation
Output Source Current
Output Sink Current
Regulator
Supply Current
V
IN
= 6V, I
OUT
≤
100μA
V
IN
= 36V, I
OUT
≤
100μA
V
IN
= 12V, I
OUT
= 125mA
(V
IN
– V
OUT
)
≥
1V, V
IN
≥
6V
(V
IN
– V
OUT
)
≥
1V, V
IN
≥
6V
6V
≤
V
IN
≤
36V
I
OUT
= 100μA
I
OUT
= 125mA
V
IN
= 12V
V
IN
= 36V
V
IN
= 36V
●
●
●
●
●
●
●
●
●
●
●
●
CONDITIONS
4.5V
≤
V
IN
≤
36V
4.5V
≤
V
IN
≤
36V
– 2mA
≤
I
REF
≤
2mA, V
IN
= 12V
V
IN
= 5V
V
IN
= 5V
●
●
●
●
●
MIN
2.40
TYP
2.50
0.01
0.4
MAX
2.55
0.02
0.8
UNITS
V
%/V
%
mA
mA
2
2
65
85
11
125
1
0.02
0.06
0.85
2.38
2.5
2.57
50
50
300
400
95
100
20
μA
μA
mA
mA
%
%/V
V
V
V
nA
μA
mA
Output Current
Load Regulation
Line Regulation
Dropout Voltage
Feedback Sense Voltage
Feedback Bias Current
Minimum Load Current
Short-Circuit Current
1120fd
3
LT1120
ELECTRICAL CHARACTERISTICS
PARAMETER
Comparator
Offset Voltage
Bias Current
Gain
Output Sink Current
Leakage Current
V
IN
= 36V (Note 2)
ΔV
OUT
= 29V, R
L
= 20k
V
IN
= 4.5V (Note 3)
V
IN
= 36V
●
●
●
●
●
The
●
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T
A
= 25°C.
CONDITIONS
MIN
TYP
MAX
10
15
1000
5
10
8
60
UNITS
mV
nA
V/V
mA
μA
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
T
A
> 85°C, I bias maximum is 100nA.
Note 3:
For T
A
≤
– 40°C output current sink drops to 2.5mA.
TYPICAL PERFOR A CE CHARACTERISTICS
Regulator Load Regulation
0.3
T
J
= –55°C
OUTPUT VOLTAGE CHANGE (%)
SUPPLY CURRENT (mA)
T
J
= 25°C
0.1
0
T
J
= 125°C
–0.1
–0.2
PRELOAD = 100μA
–0.3
0.1
1
10
100
OUTPUT CURRENT (mA)
1000
1120 G01
10
SHORT-CIRCUIT CURRENT (mA)
0.2
Dropout Voltage
REGULATOR INPUT-OUTPUT DIFFERENTIAL (V)
1
ΔV
OUT
= 100mV
MINIMUM LOAD CURRENT (μA)
RIPPLE REJECTION (dB)
0.1
0.01
0.1
10
100
1000
1
REGULATOR OUTPUT CURRENT (mA)
1120 G04
4
U W
Supply Current
100
T
J
= –55°C TO 125°C
300
250
200
150
100
50
350
Regulator Short-Circuit Current
1
0.1
CURRENT LIMIT TIED TO GROUND
0.01
0.1
10
100
1000
1
REGULATOR OUTPUT CURRENT (mA)
1120 G02
0
–50
–10
30
70
110
TEMPERATURE (°C)
150
1120 G03
Regulator Minimum Load Current
100
70
65
60
55
Regulator Ripple Rejection
I
OUT
= 100mA
I
OUT
= 10mA
50
I
OUT
= 1mA
45
40
35
V
IN
= 10VDC, 1V
P–P
V
OUT
= 5V
C
OUT
= 10μF
10
100
1k
10k
RIPPLE FREQUENCY (Hz)
100k
1120 G06
10
1
70
80
90
100 110 120 130 140 150
TEMPERATURE (°C)
1120 G05
30
1120fd
LT1120
TYPICAL PERFOR A CE CHARACTERISTICS
Supply Current
10
I
OUT
= 100mA
10
T
J
= –55°C TO 125°C
I
OUT
= 100mA
SUPPLY CURRENT (mA)
1
SUPPLY CURRENT (mA)
I
OUT
= 10mA
0.1
I
OUT
= 1mA
V
OUT
= 5V
T
J
= –55°C TO 125°C
0.01
1
5
10
15
20
25
REGULATOR INPUT-OUTPUT DIFFERENTIAL (V)
1120 G07
Reference Regulation
4
REFERENCE VOLTAGE CHANGE (mV)
3
FEEDBACK CURRENT (nA)
2
1
0
–1
–2
–3
–4
–1.5
–1.0 –0.5
0
0.5
1.0
REFERENCE OUTPUT CURRENT (mA)
Regulator Thermal Regulation
OUTPUT VOLTAGE
CHANGE (%)
0.1
V
IN
= 15V
V
OUT
= 5V
0
OUTPUT VOLTAGE (V)
–0.1
OUTPUT
CURRENT (mA)
50
0
0
20 40 60 80 100 120 140 160 180
TIME (ms)
1120 G12
U W
Supply Current at Dropout
1
I
OUT
= 10mA
0.1
I
OUT
= 1mA
0.01
1
0.1
0.2
0.3
0.4
0.5
0.6
REGULATOR INPUT-OUTPUT DIFFERENTIAL (V)
1120 G08
Feedback Pin Current
40
35
30
25
20
15
10
5
0
0.1
T
J
= 125°C
T
J
= 25°C
T
J
= –55°C
1.5
1
10
100
1000
REGULATOR OUTPUT CURRENT (mA)
1120 G11
1120 G09
LT1120 Turn-On Characteristic
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
0
0
1
2
R
L
= 50Ω
3
4
5
6
INPUT VOLTAGE (V)
7
8
V
OUT
= 5V
NO LOAD
R
L
= 500Ω
1120 G13
1120fd
5
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