REV. 0

Information furnished by Analog Devices is believed to be accurate and

reliable. However, no responsibility is assumed by Analog Devices for its

use, nor for any infringements of patents or other rights of third parties

which may result from its use. No license is granted by implication or

otherwise under any patent or patent rights of Analog Devices.

a

ADM9264

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 617/329-4700

World Wide Web Site: http://www.analog.com

Fax: 617/326-8703

© Analog Devices, Inc., 1997

FEATURES

Monitoring of 12 V, 5 V, 3.3 V and 2.8 V Supplies in

Parallel

Auxiliary Sensor Inputs

Low Power: 25

A Typical

Internal Comparator Hysteresis

Power Supply Glitch Immunity

Guaranteed from – 4 0 C to +85 C

No External Components

16-Pin Narrow SOIC Package (150 Mil Wide)

APPLICATIONS

Microprocessor Systems

Computers

Controllers

Intelligent Instruments

Network Systems

FUNCTIONAL BLOCK DIAGRAM

L

H

NC = NO CONNECT

L

H

L

H

L

H

PWROK

MONITOR

LOGIC

14

13

12

11

16

15

10

9

8

1

2

3

4

7

6

5

GND

SU1

SU2

SU3

SU4

NC

ERRX

ERR1

ERR2

PWROK

ERR3

ERR4

DIS

ERRY

SU4DET

ADM9264

Quad Power Supply Monitor

for Desktop PCs

GENERAL DESCRIPTION

The ADM9264 is a Quad Supply Monitor IC which simulta-

neously monitors four separate power supply voltages and out-

puts error signals if any of the supply voltages go out of limits.

It is designed for PC supply monitoring but can be used on

any system where multiple power supplies require monitor-

ing. The error output signals are available individually and also

gated into a common output - PWROK. Auxiliary inputs

ERRX,

ERRY are provided which are also gated into the main

PWROK signal. These inputs allow signals from other monitor-

ing circuits (for example temperature sensor, alarm, etc.) to be

linked into the ADM9264.

Each power supply monitor circuit uses a proprietary window

comparator design whereby a three resistor network is used in

conjunction with two comparators and a single precision voltage

reference to check if the supply is within its required operating

tolerance. An added feature of this design is that the power

supply voltages being monitored can be higher than the power

supply voltage to the monitoring IC itself.

Analog Devices’ experience in the design of power supply super-

visory circuits is used to provide an optimum solution for the

overall circuit in terms of cost, performance and power con-

sumption. Key features of the design include the incorporation

of hysteresis and glitch immunity into the comparators, which

minimizes the possibility of spurious triggering by noise spikes

on the supplies being monitored.

The part is manufactured on one of Analog Devices’ proprietary

BiCMOS processes, which also includes high performance thin

film resistors to achieve the accuracy required for the precision

voltage reference and power supply high and low trip points.