a
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
VCC from 2.5 V to 6 V
Guaranteed from –40؇C to +85؇C
No External Components
16-Pin Narrow SOIC Package (150 Mil Wide)
APPLICATIONS
Microprocessor Systems
Computers
Controllers
Intelligent Instruments
Network Systems
Quad Power Supply Monitor
for Desktop PCs
ADM9264
FUNCTIONAL BLOCK DIAGRAM
L
16 ERR1
GND 1
H
SU1 2
15 ERR2
L
SU2 3
H
L
SU3 4
PWROK
MONITOR
LOGIC
14 PWROK
13 ERR3
H
SU4 5
12 ERR4
L
NC 6
11 DIS
H
GENERAL DESCRIPTION
The ADM9264 is a Quad Supply Monitor IC which simultaneously monitors four separate power supply voltages and outputs 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 monitoring. 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 monitoring 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.
ERRX
7
10 ERRY
VREF
VCC
8
ADM9264
9 SU4DET
NC = NO CONNECT
Analog Devices’ experience in the design of power supply supervisory circuits is used to provide an optimum solution for the
overall circuit in terms of cost, performance and power consumption. 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.
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.
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
