© 2002 Microchip Technology Inc.

DS21377B-page 1

TC1266

Features

• Glitch Free Transition Between Input Sources

• Automatic Input Source Selection

• External PMOS Bypass Switch Control

• Built-in 5V Detector

• 1% Regulated Output Voltage Accuracy

• 200mA Load Current Capability

• Kelvin Sense Input

• Low Dropout Voltage (240mV @ Full Load)

• Low Ground Current, Independent of Load

Applications

• PCMCIA

•PCI

• Network Interface Cards (NICs)

Device Selection Table

Package Type

General Description

The TC1266 is an application-specific, low dropout

regulator (LDO), specifically intended for use in PCI

peripheral card applications complying with PCI Power

Management (PCI 2.0). It provides an uninterrupted,

3.3V, 200mA (max) output voltage when the main (5V)

or auxiliary (3.3V) input voltage supplies are present.

TheTC1266consistsof anLDO, a voltagethreshold

detector, external switchover logic and gate drive

circuitry. It functions as a conventional LDO as long as

lower threshold (3.90V typical). Should the voltage on

and an external P-channel MOSFET is automatically

turned on, connecting the auxiliary supply input to

main supply is automatically selected, if both the main

and auxiliary input supplies are present, and transition

from one input supply to the other is ensured glitch-

free. High integration, automatic secondary supply

switchover, Kelvin sensing, and small size make the

TC1266 the optimum LDO for PCI 2.0 applications.

Functional Block Diagram

Part Number

Package

Junction

Temp. Range

TC1266VOA 8-Pin SOIC (Narrow) -5°C to +125°C

TC1266VUA

8-Pin MSOP

-5°C to +125°C

1

2

3

4

8

7

6

5

TC1266

SENSE

NC

8-Pin SOIC

NC

GND

1

2

3

4

8

7

6

5

TC1266

8-Pin MSOP

NC

GND

SENSE

NC

+

–

GND

SENSE

Bandgap

Reference

Detect

E/A

200mA PCI LDO