LT3150 View Datasheet(PDF) - Linear Technology

Part Name

Description

Manufacturer

LT3150

Fast Transient Response, Low Input Voltage, Very Low Dropout Linear Regulator Controller

Linear Technology 

TYPICAL APPLICATIO S

Setting the Linear Regulator Output Voltage

VOUT

R2

FB2

R1

VOUT = 1.21V(1 + R2/R1)

3150 TA03

Setting Current Limit

IPOS

INEG

GATE

VIN1

RSENSE*

Q2

VOUT

*ILIM = 50mV/RSENSE

RSENSE = DISCRETE SHUNT RESISTOR OR

RSENSE = KELVIN-SENSED PC BOARD TRACE

ACTIVATING CURRENT LIMIT ALSO ACTIVATES

THE SHDN2 PIN TIMER

3150 TA05

Shutdown Time-Out with Reset

RESET

0V TO 5V

Q1

VN2222L

R1

100k

SHDN2

C1*

*C1 = 15µA(t)/1.11V

t = SHUTDOWN LATCHOFF TIME 3150 TA07

Shutdown Time-Out with Reset

R2

RESET 100k

0V TO 5V

Q2

2N3904

R3

100k

SHDN2

C2*

*C2 = 15µA(t)/1.11V

t = SHUTDOWN LATCH-OFF TIME

3150 TA09

LT3150

Using No RSENSE Current Limit

SHDN2 IPOS

CT

INEG

GATE

D1

MBR0520L

VIN1

C1

10µF

Q1

VOUT 3150 TA04

Current Limit with Foldback Limiting Example

IPOS

VIN1

INEG

GATE

R5

D1

1N4148

D2

1N4148

R4

IOUT

Q3

R6

VOUT

3150 TA06

SET R5 << R6

( ) ( ) IOUT

=

50mV

R4

R6 – (VIN1 – VOUT – 2VF) R5

R5 + R6

R4

R5 + R6

Basic Thermal Shutdown

VIN1

RT1

10k

NTC

SHDN2

R4*

RT1 = DALE NTHS-1206N02

THERMALLY MOUNT RT1

IN CLOSE PROXIMITY

TO THE EXTERNAL

N-CHANNEL MOSFET

*CHOOSE R4 BASED ON

VIN1 AND REQUIRED THERMAL

SHUTDOWN TEMPERATURE

3150 TA08

Overvoltage Protection

VOUT

R6

SHDN2

R5

3150 TA10

VOUT(uth) = 1.21(R6/R5) + 5µA(R6)

VOUT(lth) = 1.11(R6/R5) – 15µA(R6)

3150f

17

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