Linear Technology LT1120 Datasheet

FEATURES

LT1120

Micropower Regulator with

Comparator and Shutdown

U

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, SO and Metal Can Packages

U

APPLICATIO S

■

Battery Systems

■

Battery-Backup System

■

Portable Terminals

■

Portable Instruments

■

Memory Keep-Alive

U

TYPICAL APPLICATIO

The LT®1120 is a combination micropower positive regu­lator 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 moni­toring. 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.

, LTC and LT are registered trademarks of Linear Technology Corporation.

V

IN

I

Q

> 5.2V

= 40µA

5V Regulator

5

V

IN

+ +

10µF

LT1120

SHUTDOWN

4

V

OUT

0.001µF1M

2

FB

GNDSHDN

13

1M

25µF

1120 TA01

Dropout Voltage and Supply Current

5V

1.00

0.10

DROPOUT VOLTAGE (V)

0.01

0.1 1
OUTPUT CURRENT (mA)

10 100 1000

10

SUPPLY CURRENT (mA)

1

0.1

1120 TA02

1

LT1120

TOP VIEW

COMPOUT

–INPUT

GND

FB REF

V

IN

SHDN

V

OUT

8

7

6

5

3

2

1

4

H PACKAGE

8-LEAD TO-5 METAL CAN

WW

W

ABSOLUTE AXI U RATI GS

U

(Note 1)

Input Voltage ........................................................... 36V

NPN Collector Voltage ............................................. 36V

Output Short-Circuit Duration.......................... Indefinite

Power Dissipation............................... Internally Limited

UUW

PACKAGE/ORDER I FOR ATIO

GND

1

FB

2

SHDN

3

V

4

OUT

J8 PACKAGE

8-LEAD CERDIP

S8 PACKAGE

8-LEAD PLASTIC SO

T

= 150°C, θJA = 100°C/W (J)

JMAX

= 110°C, θJA = 130°C/W (N)

T

JMAX

= 110°C, θJA = 150°C/W (S)

T

JMAX

TOP VIEW

N8 PACKAGE
8-LEAD PDIP

–INPUT

8

COMPOUT

7

REF

6

V

5

IN

ORDER PART

NUMBER

LT1120CJ8
LT1120CN8
LT1120CS8
LT1120IN8
LT1120IS8

S8 PART MARKING

1120
1120I

Operating Temperature Range

LT1120C................................................ 0°C to 100°C

LT1120I ................................................ –40 to 100°C

Storage Temperature Range ................. –65°C to 150°C

ORDER PART

NUMBER

LT1120CH

T

= 150°C, θJA = 150°C/W, θJC = 45°C/W

JMAX

Consult factory for Military grade parts.

ELECTRICAL CHARACTERISTICS

operating temperature range, otherwise specifications are at T

PARAMETER CONDITIONS MIN TYP MAX UNITS

Reference

Reference Voltage 4.5V ≤ VIN ≤ 36V 2.46 2.50 2.54 V
Line Regulation 4.5V ≤ VIN ≤ 36V 0.01 0.015 %/V
Load Regulation –2mA ≤ I
Output Source Current VIN = 5V 2 4 mA
Output Sink Current VIN = 5V 2 4 mA
Temperature Stability 1%

Regulator

Supply Current VIN = 6V, I

Output Current (VIN – V
Load Regulation (VIN – V
Line Regulation 6V ≤ VIN ≤ 36V 0.01 0.015 %/V
Dropout Voltage I

Feedback Sense Voltage VIN = 12V 2.44 2.5 2.56 V
Shutdown Pin Voltage Normal 0.4 V

The ● denotes the specifications which apply over the full

= 25°C. Tj = 25°C

A

≤ 2mA, VIN = 12V 0.3 0.6 %

REF

≤ 100µA4580µA

OUT

= 36V, I

V

IN

V

= 12V, I

IN

= 100µA 0.02 0.05 V

OUT

I

= 125mA 0.4 0.65 V

OUT

V

≤ 0.5V Shutdown 2.2 1.4 V

OUT

≤ 100µA 75 100 µA

OUT

= 125mA 11 20 mA

OUT

) ≥ 1V, VIN ≥ 6V 125 mA

OUT

) ≥ 1V, VIN ≥ 6V 0.2 0.5 %

OUT

2

LT1120

ELECTRICAL CHARACTERISTICS

operating temperature range, otherwise specifications are at T

PARAMETER CONDITIONS MIN TYP MAX UNITS

Shutdown Pin Current VIN = 1.4V 25 µA
Feedback Bias Current 15 40 nA
Minimum Load Current VIN = 36V 15 µA
Short-Circuit Current VIN = 36V 300 400 mA

Comparator

Offset Voltage VIN = 36V 37mV
Bias Current VIN = 36V (Note 2) 15 40 nA
Gain ∆V
Power Supply Rejection 4.5V ≤ VS ≤ 36V 80 96 dB
Output Sink Current VIN = 4.5V 10 18 mA
Saturation Voltage I
Input Voltage Range 0V
Response Time 5 µs
Leakage Current 2 µA

= 29V, RL = 20k 2000 10000 V/V

OUT

= 1mA 0.4 0.6 V

OUT

The ● denotes the specifications which apply over the full

= 25°C. Tj = 25°C

A

– 1 V

IN

ELECTRICAL CHARACTERISTICS

The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C.

PARAMETER CONDITIONS MIN TYP MAX UNITS

Reference

Reference Voltage 4.5V ≤ VIN ≤ 36V ● 2.40 2.50 2.55 V
Line Regulation 4.5V ≤ VIN ≤ 36V ● 0.01 0.02 %/V
Load Regulation –2mA ≤ I
Output Source Current VIN = 5V ● 2mA
Output Sink Current VIN = 5V ● 2mA

Regulator

Supply Current VIN = 6V, I

= 36V, I

V

IN

V

= 12V, I

IN

Output Current (VIN – V
Load Regulation (VIN – V
Line Regulation 6V ≤ VIN ≤ 36V ● 0.02 %/V
Dropout Voltage I

Feedback Sense Voltage VIN = 12V ● 2.38 2.5 2.57 V
Feedback Bias Current ● 50 nA
Minimum Load Current VIN = 36V ● 50 µA
Short-Circuit Current VIN = 36V ● 300 400 mA

OUT

I

OUT

≤ 2mA, VIN = 12V ● 0.4 0.8 %

REF

≤ 100µA ● 65 95 µA

OUT

≤ 100µA ● 85 100 µA

OUT

= 125mA ● 11 20 mA

OUT

) ≥ 1V, VIN ≥ 6V ● 125 mA

OUT

) ≥ 1V, VIN ≥ 6V ● 1%

OUT

= 100µA ● 0.06 V
= 125mA ● 0.85 V

3

LT1120

ELECTRICAL CHARACTERISTICS

The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C.

PARAMETER CONDITIONS MIN TYP MAX UNITS

Comparator

Offset Voltage ● 10 mV
Bias Current VIN = 36V (Note 2) ● 15 60 nA
Gain ∆V
Output Sink Current VIN = 4.5V (Note 3) ● 510 mA
Leakage Current VIN = 36V ● 8 µA

= 29V, RL = 20k ● 1000 V/V

OUT

Note 1: Absolute Maximum Ratings are those values beyond which the life
a device may be impaired.

Note 2: TA > 85°C, I bias maximum is 100nA.
Note 3: For TA ≤ –40°C output current sink drops to 2.5mA.

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Regulator Load Regulation Supply Current Regulator Short-Circuit Current

0.3

0.2

0.1

0

–0.1

OUTPUT VOLTAGE CHANGE (%)

–0.2

PRELOAD = 100µA

–0.3

0.1 10 100 1000

TJ = –55°C

TJ = 25°C

TJ = 125°C

1
OUTPUT CURRENT (mA)

1120 G01

100

TJ = –55°C TO 125°C

10

1

SUPPLY CURRENT (mA)

0.1

0.01

0.1 1
REGULATOR OUTPUT CURRENT (mA)

10 100 1000

1120 G02

350

300

250

200

150

100

SHORT-CIRCUIT CURRENT (mA)

CURRENT LIMIT TIED TO GROUND

50

0

–50 –10 30 70 110 150

TEMPERATURE (°C)

1120 G03

Dropout Voltage

1

∆V

= 100mV

OUT

0.1

REGULATOR INPUT-OUTPUT DIFFERENTIAL (V)

0.01

0.1 1
REGULATOR OUTPUT CURRENT (mA)

10 100 1000

4

1120 G04

Regulator Minimum Load Current Regulator Ripple Rejection

100

10

MINIMUM LOAD CURRENT (µA)

1

70 80 90 100 110 120 130 140 150

TEMPERATURE (°C)

1120 G05

70

65

60

55

I

= 10mA

OUT

50

45

RIPPLE REJECTION (dB)

40

35

30

10 1k 10k 100k

I

= 1mA

OUT

VIN = 10VDC, 1V
V

= 5V

OUT

= 10µF

C

OUT

100

RIPPLE FREQUENCY (Hz)

P–P

I

OUT

= 100mA

1120 G06