Microprocessor Supervisory

Circuit in 4-Lead SOT-143 with DSP

Data Sheet

ADM811/ADM812

Rev. G

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FEATURES

Superior upgrade for MAX811/MAX812

Specified over temperature

Low power consumption: 5 µA typical

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

Power-on reset: 140 ms minimum

Logic low RESET output (ADM811)

Logic high RESET output (ADM812)

Built-in manual reset

APPLICATIONS

Microprocessor systems

Controllers

Intelligent instruments

Automotive systems

Safety systems

Portable instruments

FUNCTIONAL BLOCK DIAGRAM

RESET

GENERATOR

DEBOUNCE

RESET/RESET

GND

MR

ADM811/ADM812

Figure 1.

GENERAL DESCRIPTION

The ADM811/ADM812 are reliable voltage monitoring devices

suitable for use in most voltage monitoring applications. The

ADM811/ADM812 are designed to monitor six different

voltages, each allowing a 5% or 10% degradation of standard

PSU voltages before a reset occurs. These voltages have been

selected for the effective monitoring of 2.5 V, 3 V, 3.3 V, and 5 V

supply voltage levels.

Included in this circuit is a debounced manual reset input.

Reset can be activated using an electrical switch (or an input

from another digital device) or by a degradation of the supply

voltage. The manual reset function is very useful, especially if

the circuit in which the ADM811/ADM812 are operating enters

into a state that can only be detected by the user. Allowing the

user to reset a system manually can reduce the damage or

danger that could otherwise be caused by an out-of-control

or locked system.

ADM811

GND

MR

RESET

MICROPROCESSOR

SYSTEM

GND

RESET

100kΩ

Figure 2. Typical ADM811 Operating Circuit