 2001-2012 Microchip Technology Inc.

DS21437C-page 1

TC57

Features

• Low Dropout Voltage: 100mV @ 650mA with

FZT749 PNP Transistor

• 2.7V to 8V Supply Range

• Low Operating Current: 50

A Operating,

0.2

A Shutdown

• Low True Chip Enable

• Output Accuracy < ±2%

• Small Package: 5-Pin SOT-23A

Applications

• Battery Operated Systems

• Portable Instruments

• High-Efficiency Linear Regulator

• Post-Regulator for SMPS

• Power Supply or Battery Back-Up Supply for

Memory

Device Selection Table

Other output voltages and package options are available.

Please contact Microchip Technology Inc. for details.

Package Type

General Description

The TC57 is a low dropout regulator controller that

operates with an external PNP pass transistor, allowing

the user to tailor the LDO characteristics to suit the

application at hand. This results in lower dropout

operation (and often lower cost) compared with

traditional

linear

regulators

with

on-board

pass

transistors. The maximum output current of a TC57-

based

regulator

circuit

is

limited

only

by

the

characteristics of the external pass transistor. For

example, a maximum output current of 650mA (with a

dropout voltage of 100mV) results when an FZT749

pass transistor is used, while a Darlington configuration

can deliver up to 4A.

Flexibility, and superior performance make this family

of regulator controllers the ideal choice in applications

where low dropout voltage and low installed cost are

key.

Functional Block Diagram

Part Number

Output

Voltage

Package

Temperature

Range

TC572502ECT

2.5V

5-Pin SOT-23A -40°C to +85°C

TC573002ECT

3.0V

5-Pin SOT-23A -40°C to +85°C

TC573302ECT

3.3V

5-Pin SOT-23A -40°C to +85°C

SHDN

5

5-Pin SOT-23A

TC57

13

4

EXT

2

GND

NOTE: 5-Pin SOT-23A is equivalent to the EIAJ SC-74A.

TC573002ECT

GND

SHDN

EXT

10μF

(Tantalum)

FZT749

Q1

1K

10

μF

(Tantalum)

47K

1

2

ON

OFF

3

4

5

3.3V Line Input, 3.0V, 500mA Output LDO

Line Regulator Controller