General Description

These microprocessor (µP) supervisory circuits reduce the

complexity and number of components required for pow-

er-supply monitoring and battery-control functions in µP

systems. They significantly improve system reliability and

accuracy compared to separate ICs or discrete components.

These devices are designed for use in systems powered

by 3.0V or 3.3V supplies. See the selector guide in the

back of this data sheet for similar devices designed for

5V systems. The suffixes denote different reset threshold

voltages: 3.075V (T), 2.925V (S), and 2.625V (R) (see the

Reset Threshold section in the Detailed Description). All

these parts are available in 8-pin DIP and SO packages.

Functions offered in this series are as follows:

Features

● RESET and RESET Outputs

● Manual Reset Input

● Precision Supply-Voltage Monitor

● 200ms Reset Time Delay

● Watchdog Timer (1.6sec timeout)

● Battery-Backup Power Switching—Battery Can

● 1µA Battery Supply Current

● Voltage Monitor for Power-Fail or Low-Battery

Warning

● 8-Pin DIP and SO Packages

Applications

● Battery-Powered Computers and Controllers

● Embedded Controllers

● Intelligent Instruments

● Critical µP Power Monitoring

● Portable Equipment

19-0243; Rev 3; 4/15

Pin Configuration appears at end of data sheet.

Typical Operating Circuits continued at at end of data

sheet.

Ordering Information continued at end of data sheet.

*Contact factory for dice specifications.

**These parts offer a choice of reset threshold voltage. Select

the letter corresponding to the desired nominal reset threshold

voltage (T = 3.075V, S = 2.925V, R = 2.625V) and insert it into

the blank to complete the part number.

Devices in PDIP and SO packages are available in both leaded

and lead(Pb)-free packaging. Specify lead free by adding the +

symbol at the end of the part number when ordering. Lead free

not available for CERDIP package.

PART**

TEMP RANGE

PIN-PACKAGE

MAX690_CPA

0°C to +70°C

8 Plastic DIP

MAX690_CSA

0°C to +70°C

8 SO

MAX690_C/D

0°C to +70°C

Dice*

MAX690_EPA

-40°C to +85°C

8 Plastic DIP

MAX690_ESA

-40°C to +85°C

8 SO

MAX690_MJA

-55°C to +125°C

8 CERDIP

MAX690T/S/R

MAX802T/S/R

MAX804T/S/R

MAX805T/S/R

0.1µF

RESET

(RESET)

PFO

WDI

R1

VBATT

GND

GND

GND

0.1µF

0.1µF

3.6V

LITHIUM

BATTERY

CMOS RAM

µP

RESET

NMI

I/O LINE

UNREGULATED

DC

REGULATED +3.3V OR +3.0V

R2

BUS

( ) ARE FOR MAX804T/S/R, MAX805T/S/R

PFI

MAX690







±4%



±75mV

MAX704







±4%



±75mV

MAX802







±2%



±2%

MAX804







±2%



±2%

MAX805







±4%



±75mV

MAX806







±2%



±2%

MAX690T/S/R, MAX704T/S/R,

MAX802T/S/R, MAX804‒MAX806T/S/R

3.0V/3.3V Microprocessor

Supervisory Circuits

Typical Operating Circuits

Ordering Information