Low-Voltage Manual Reset & Watchdog

Supervisory Circuits in 4-Lead SC70

Preliminary Technical Data

ADM8611/ADM8616/ADM8617/ADM8618

Rev. PrB

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FEATURES

Precision 1.8V to 5V Power Supply Monitoring

9 Reset Threshold Options:

1.58V to 4.63V

140ms (Min) Reset Timeout

Manual Reset Input (ADM8611)

Watchdog Timer (ADM8616–ADM8618)

Reset Output Stages

Push-Pull Active-Low

Open-Drain Active-Low

Push-Pull Active-High

Low Power Consumption (3µA)

Power Supply Glitch Immunity

Specified Over -40°C to +85°C Temperature Range

4-Lead SC70 Package

APPLICATIONS

Microprocessor Systems

Computers

Controllers

Intelligent Instruments

Portable Equipment

GENERAL DESCRIPTION

The ADM8611/ADM8616/ADM8617/ADM8618 are

supervisory circuits which monitor power supply voltage levels

and code execution integrity in microprocessor-based systems.

A power-on-reset signal is generated when the supply voltage

rises to a preset threshold level. The ADM8611’s debounced

manual reset input can be used to initiate a reset by means of an

external push-button or logic signal. The ADM8616–ADM8618

have an on-chip watchdog timer which can reset the

microprocessor if it fails to strobe within a preset timeout

period.

FUNCTIONAL BLOCK DIAGRAMS

RESET

GENERATOR

GND

RESET

ADM8616

WATCHDOG

DETECTOR

WDI

Figure 1.

Each part is available in a choice of the following 9 reset

threshold options: 1.58V, 1.67V, 2.19V, 2.32V, 2.63V, 2.93V,

3.08V, 4.38V and 4.63V. The reset timeout periods are 20ms

(min) and 140ms (min) for the ADM8611 and ADM8616–

ADM8618, respectively. The watchdog timeout period is 1.6s

(typ). The parts differ in terms of reset output configuration, as

indicated in table 1.

The ADM8611/ADM8616/ADM8617/ADM8618 are available

in 4-lead SC70 packages and typically consume only 3µA,

making them suitable for use in low power portable

applications.

Table 1. Selection Table

Output Stage

Part No.

Manual Reset

Watchdog

RESET

RESET

ADM8611

Yes

-

Push-Pull

ADM8616

-

Yes

Push-Pull

ADM8617

-

Yes

Open-Drain

ADM8618

-

Yes

Push-Pull