© 2000 SEMTECH CORP.

652 MITCHELL ROAD NEWBURY PARK CA 91320

500mA SmartLDO

Signal Sequencing

SC1545

PRELIMINARY - January 17, 2000

1

TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com

DESCRIPTION

The SC1545 was designed for instantly available moth-

erboard applications. As part of the Semtech family of

SmartLDO’s it provides additional control functions not

available in a standard LDO.

The device provides the capability to control three sep-

arate supplies. There is an on-board 500mA, 2.5V

LDO with current limit protection, and drive pins for an

N-channel MOSFET and a P-channel MOSFET. Inter-

nal logic circuitry ensures that the system starts up in a

controlled manner, and that the correct outputs are en-

abled during specific sequences of BF_CUT and SLP.

The LDO draws its power from the 5V standby supply,

and the N-channel MOSFET drive is derived from the

12V supply.

The SC1545 is available in the surface mount SO-8

package.

FEATURES

temperature

APPLICATIONS

ORDERING INFORMATION

Part Number

(1)

Package

SC1545CS

SO-8

Note:

(1) Add suffix ‘TR’ for tape and reel packaging.

TYPICAL APPLICATION CIRCUIT

2.5V OUT

5V STANDBY

12V IN

BF_CUT

SLP

2.5V IN

2.5V OUT

3.3V IN

3.3V OUT

U1

SC1545

1

2

3

4

5

6

7

8

VO

GND

PDR

NDR

SLP

BF_CUT

12VIN

5VSTBY

C5

10uF

C6

1uF

C7

0.1uF

C1

2 x 100uF

Q1

Si4410

Q2

IRLMS6802

C2

100uF

C3

2 x 100uF

C4

100uF