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ADM803/ADM809/ADM810

Microprocessor Supervisory Circuits

in 3-Lead SC70 and SOT-23

FEATURES

Specified over Temperature

Low Power Consumption (17

A)

Precision Voltage Monitor: 2.5 V, 3 V, 3.3 V, 5 V Options

140 ms Min 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 DIAGRAM

RESET

GENERATOR

240ms

RESET

(RESET)

GND

ADM809 /ADM810

RESET

GENERATOR

240ms

ADM803

RESET

GND

RESET

RESET

INPUT

GND

GND

MICROPROCESSOR

SYSTEM

ADM803 /ADM809

*ADM803 ONLY

Figure 1. Typical Operating Circuit

GENERAL DESCRIPTION

The ADM803/ADM809/ADM810 supervisory circuits monitor

the power supply voltage in microprocessor systems. They pro-

vide 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 remains opera-

provide an active low reset signal (

RESET), while 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. Refer to Table I.

The reset comparator features built-in glitch immunity, making

The ADM803/ADM809/ADM810 consume only 17

µA, making

it suitable for low power portable equipment. The ADM803 is

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

in 3-lead SOT-23 and SC70 packages.