1

LT3150

3150f

Fast Transient Response,

Low Input Voltage, Very Low Dropout

Linear Regulator Controller

1.8V to 1.5V, 4A Very Low Dropout Linear Regulator

50mV/DIV

2A/DIV

20

µs/DIV

3150 TA02

Transient Response for

0.1A to 4A Output Load Step

s

Microprocessor, ASIC and I/O Supplies

s

Very Low Dropout Input-to-Output Conversion

s

Logic Termination Supplies

s

Fast Transient Response Optimized with

Ceramic Output Capacitors

s

s

±1% Reference Tolerance Over Temperature

s

Multifunction LDO Shutdown Pin with Latchoff

s

Fixed Frequency 1.4MHz Boost Converter Generates

MOSFET Gate Drive

s

Internally Compensated Boost Converter Uses Tiny

Capacitors and Inductor

s

Independent Boost Converter Shutdown Control

Permits LDO Output Voltage Supply Sequencing

s

16-Lead SSOP Package

The LT

as a source follower to produce a fast transient response,

very low dropout voltage linear regulator. Selection of the

The LT3150 includes a fixed frequency boost regulator

that generates gate drive for the N-channel MOSFET. The

internally compensated current mode PWM architecture

combined with the 1.4MHz switching frequency permits

the use of tiny, low cost capacitors and inductors.

The LT3150’s transient load performance is optimized

with ceramic output capacitors. A precision 1.21V refer-

ence accommodates low voltage supplies.

Protection includes a high side current limit amplifier that

activates a fault timer circuit. A multifunction shutdown

pin provides either current limit time-out with latchoff,

overvoltage protection or thermal shutdown. Independent

shutdown control of the boost converter provides on/off

and sequencing control of the LDO output voltage.

+

FB1

SHDN2

SWGND

GND

GND

SW

SHDN1

GATE

FB2

COMP

LT3150

MBR0520L

L1

10

µH

1.5k

C1: AVX TAJA475M020R 20V 20%

L1: MURATA LQH32CN100K11 OR SUMIDA CDRH3D16100

243

Ω

1%

1020

Ω

1%

C1

4.7

µF

+

220

µF

2.5V

×2

1.8V

1.5V

4A

6.19k

1%

1.37k

1%

Si4410

3150 TA01

2.2

µF ×10

X5R CERAMIC

0805 CASE

5.1

Ω

6800pF

50pF

DESCRIPTIO

FEATURES

APPLICATIO S

TYPICAL APPLICATIO

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