ST LK112SM13TR, LK112SM14TR, LK112SM18TR, LK112SM19TR, LK112SM20TR User Manual

Low noise low drop voltage regulator with shutdown function

Features

■ Output current up to 200 mA

■ Low dropout voltage (500 mV max at

I

= 200 mA)

OUT

■ Very low quiescent current: 0.1 µA in OFF

mode and max 250 µA in ON mode at
I

= 0 mA

OUT

■ Low output noise: typ. 30 µV at I

and 10 Hz < f < 80 kHz

■ Wide range of output voltages

■ Internal current and thermal limit

■ V

■ Operative input voltage from:

tolerance ± 2% (at 25 °C)

OUT

V

+ 0.5 to 14 V (for V

OUT

OUT

or from 2.5 V to 14 V (for V

> 2 V)

OUT

Description

The LK112Sxx is a low dropout linear regulator
with a built in electronic switch. The internal
switch can be controlled by TTL or CMOS logic
levels. The device is ON state when the control
pin is pulled to a logic high level. An external
capacitor can be used connected to the noise
bypass pin to lower the output noise level to 30

OUT

< 2 V)

= 60 mA

LK112Sxx

SOT23-5L

µVrms. An internal PNP pass transistor is used to
achieve a low dropout voltage.

The LK112Sxx has a very low quiescent current
in ON MODE while in OFF MODE the Iq is
reduced down to 100 nA max. The internal
thermal shutdown circuitry limits the junction
temperature to below 150 °C. The load current is
internally monitored and the device will shutdown
in the presence of a short circuit or overcurrent
condition at the output.

Table 1. Device summary

Part numbers

LK112SXX13 LK112SXX24 LK112SXX36 LK112SXX45

LK112SXX14 LK112SXX26 LK112SXX37 LK112SXX46

LK112SXX18 LK112SXX28 LK112SXX38 LK112SXX47

LK112SXX19 LK112SXX29 LK112SXX39 LK112SXX48

LK112SXX20 LK112SXX31 LK112SXX41 LK112SXX49

LK112SXX21 LK112SXX33 LK112SXX42 LK112SXX50

LK112SXX22 LK112SXX34 LK112SXX43

LK112SXX23 LK112SXX35 LK112SXX44

July 2008 Rev 11 1/17

www.st.com

17

Contents LK112Sxx

Contents

1 Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

5 Typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

6 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

7 Order codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

8 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

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LK112Sxx Diagram

1 Diagram

Figure 1. Schematic diagram

3/17

Pin configuration LK112Sxx

2 Pin configuration

Figure 2. Pin connection (top view)

Table 2. Pin description

Pin n° Symbol Note

1 SHDN

2GND

3 Bypass Bypass Pin: Bypass with 0.1 µF to improve the V

4 OUT Output port

5 IN Input port

Shutdown Input: Disables the regulator when is connected to GND or to positive
voltage less than 0.6 V

Ground Pin: Internally connected to the die attach flag to decrease the total thermal
resistance and increase the package ability to dissipate power.

thermal noise performances.

REF

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LK112Sxx Maximum ratings

3 Maximum ratings

Table 3. Absolute maximum ratings

Symbol Parameter Value Unit

V

SHDN

T

T

V

I

I

O

STG

OP

DC input voltage 16 V

DC input voltage 16 V

Output current Internally limited

Storage temperature range -55 to 150 °C

Operating junction temperature range -40 to 125 °C

Table 4. Thermal data

Symbol Parameter SOT23-5L Unit

R

thJC

R

thJA

Thermal resistance junction-case 81 °C/W

Thermal resistance junction-ambient 255 °C/W

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Electrical characteristics LK112Sxx

4 Electrical characteristics

Table 5. Electrical characteristics for LK112S (TJ = 25 °C, VIN=V

V

= 1.8 V, CI = 1 µF, CO = 2.2 µF, C

SHDN

BYPASS

= 0.1 µF unless otherwise specified)

OUT

+1 V

(1)

, I

OUT

= 0mA,

Symbol Parameter Test conditions Min. Typ. Max. Unit

I

Quiescent current

d

V

Output voltage IO = 30mA (see table)

O

ΔV

ΔV

Line regulation

O

Load regulation

O

V

Dropout voltage

d

Short circuit current 200 mA

I

SC

SVR Supply voltage rejection

eN Output noise voltage

I

SHDN

Shutdown input current V

ON MODE (except I

(2)

(2)

= 8V, V

I

BYP

OFF MODE, V

V

= VO+1V to VO+6V, VO ≤ 5.6V 0.7 20 mV

I

= VO+1V to VO+6V, VO > 5.6V 0.8 40 mV

V

I

I

= 1 to 60mA 15 30 mV

O

= 1 to 200mA 30 90 mV

I

O

I

= 60 mA

O

I

= 200 mA

O

= VO+1.5V, C

V

I

= 10µF, f = 400Hz, IO = 30mA

C

O

B= 10Hz to 80kHz, C
CO = 10µF, VI = VO+1.5V, IO = 60mA

= 1.8V, Output ON 12 35 µA

SHDN

)175250µA

SHDN

= 0V 0 0.1 µA

SHDN

0.17 0.24 V

0.35 0.5 V

= 0.1µF

= 0.1µF

BYP

55 dB

30 µVrms

Output ON 1.8

V

Shutdown input logic

SHDN

Output OFF 0.6

V

ΔVO/T

1. For version with output voltage less than 2V VIN=2.4V

2. Only for version with output voltage more than 2.1V

Output voltage

J

temperature coefficient

= 10mA 0.09 mV/°C

I

O

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