© 2000 California Micro Devices Corp. All rights reserved.

10/18/2000

1

CMPWR025

CALIFORNIA MICRO DEVICES

215 Topaz Street, Milpitas, California 95035



Tel: (408) 263-3214

Fax: (408) 263-7846

www.calmicro.com

Dual Input SmartOR™ Power Switch

FEATURES

• Automatically selects V

• Integrated low impedance switches (0.2

Ω TYP)

• Operating supply range from 2.8V to 5.5V

• Glitch-free output during supply switching

transitions

• Low operating supply current of 20µA (TYP)

• User-selectable hysteresis for supply selection

• 8-pin SOIC Narrow or 8-pin MSOP packages

PRODUCT DESCRIPTION

California Micro Devices’ SmartOR™ CMPWR025 is a

dual input power switch that selects between two

different power inputs and delivers it to one output. The

device integrates two very low impedance power

switches and automatically implements an OR function

that selects the higher of the two inputs. A hysteresis is

built in (and is user selectable) to prevent switch chatter.

The CMPWR025 is a much-improved solution to simply

ORing two diodes, due to the greatly reduced losses of

the CMPWR025 when compared to low forward drop

Schottky diodes.

APPLICATIONS

• PCI cards for Wake-On-LAN/Wake-On-Ring

• Dual power systems

• Systems with standby capabilities

• Battery backup systems

• See Application Note AP211

C0970500

PIN DIAGRAM, TYPICAL APPLICATION CIRCUIT, AND SIMPLIFIED BLOCK DIAGRAM

The CMPWR025 is designed to operate above the 1W

(375mA at 3.3V) sleep mode rating stated in the PCI

Rev 2.2 spec. In fact the CMPWR025 current rating is

dependent upon the power dissipation resulting from the

voltage drop across the internal switch elements. See

the Typical DC Characteristics section in this data sheet

for details.

For IAPC (Instantly Available Personal Computer)

applications see the CAMD Applications Note AP211

“Instantly Available PCI Card Power Management”.

Pin Diagram

Typical Application Circuit

Simplified Block Diagram

1

2

3

4

8

7

6

5

HYS

GND

Top View

CMPWR025

8-Pin SOIC Narrow and MSOP Package

HYS

5V

GND

GND

CMPWR025

5V

10µF

+

+

–

+

–

+

–

HYS

SW2

0.2

Ω

SW1

0.2

Ω

GND

GND

GND

GND