Microprocessor Supervisory Circuits

in 3-Lead SC70 and SOT-23

ADM803/ADM809/ADM810

Rev. H

Information furnished by Analog Devices is believed to be accurate and reliable. However, no

responsibilityis assumedbyAnalogDevicesforitsuse,norforanyinfringementsof patentsorother

rightsofthirdpartiesthatmayresultfromitsuse.Specificationssubjecttochangewithoutnotice.No

license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

Trademarksandregisteredtrademarksarethepropertyoftheirrespectiveowners.

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

Tel: 781.329.4700

www.analog.com

Fax: 781.461.3113

©1997–2008 Analog Devices, Inc. All rights reserved.

FEATURES

Specified over temperature

Low power consumption: 17 μA

Precision voltage monitor: 2.5 V, 3 V, 3.3 V, 5 V options

140 ms minimum power-on reset

Open-drain RESET output (ADM803)

Push-pull RESET output (ADM809)

Push-pull RESET output (ADM810)

SC70 and SOT-23 packages

APPLICATIONS

Microprocessor systems

Computers

Controllers

Intelligent instruments

Automotive systems

FUNCTIONAL BLOCK DIAGRAMS

GND

GND

ADM803/ADM809

MICROPROCESSOR

SYSTEM

*ADM803 ONLY

RESET

INPUT

RESET

ADM803

GND

RESET

GENERATOR

240ms

RESET

RESET

(RESET)

GND

RESET

GENERATOR

240ms

ADM809/ADM810

Figure 1.

GENERAL DESCRIPTION

The ADM803/ADM809/ADM810 supervisory circuits monitor

the power supply voltage in microprocessor systems. They

provide a reset output during power-up, power-down, and

brownout conditions. On power-up, an internal timer holds

reset asserted for 240 ms. This holds the microprocessor in a

reset state until conditions have stabilized. The reset output

ADM809 provide an active low reset signal (RESET), whereas

the ADM810 provides an active high signal (RESET) output.

The ADM809 and ADM810 have push-pull outputs, whereas

the ADM803 has an open-drain output, which requires an

external pull-up resistor.

Seven reset threshold voltage options are available, suitable for

monitoring a variety of supply voltages (see Table 3).

The reset comparator features built-in glitch immunity, making

The ADM803/ADM809/ADM810 consume only 17 μA, making

them suitable for low power, portable equipment. The ADM803

is available in a 3-lead SC70; the ADM809/ADM810 are available

in 3-lead SOT-23 and 3-lead SC70 packages.