General Description

The MAX807 microprocessor (µP) supervisory circuit

reduces the complexity and number of components

needed to monitor power-supply and battery-control func-

tions in µP systems. A 70µA supply current makes the

MAX807 ideal for use in portable equipment, while a 2ns

chip-enable propagation delay and 250mA output current

capability (20mA in battery-backup mode) make it suit-

able for larger, higher-performance equipment.

The MAX807 comes in 16-pin DIP, SO, and TSSOP pack-

ages, and provides the following functions:

•µP reset. The active-low RESET output is asserted dur-

ing power-up, power-down, and brownout conditions,

down to 1V.

• Active-high RESET output.

• Manual-reset input.

• Two-stage power-fail warning. A separate low-line

the reset threshold. This low-line comparator is more

accurate than those in previous µP supervisors.

• Backup-battery switchover for CMOS RAM, real-time

clocks, µPs, or other low-power logic.

• Write protection of CMOS RAM or EEPROM.

• 2.275V threshold detector provides for power-fail

warning and low-battery detection, or monitors a

power supply other than +5V.

• BATT OK status flag indicates that the backup-battery

voltage is above +2.275V.

• Watchdog-fault output—asserted if the watchdog input

has not been toggled within a preset timeout period.

Applications

Computers

Controllers

Intelligent Instruments

Critical µP Power Monitoring

Portable/Battery-Powered Equipment

Features

♦ Precision 4.675V (MAX807L), 4.425V (MAX807M),

or 4.575V (MAX807N) Voltage Monitoring

♦ 200ms Power-OK/Reset Time Delay

♦ RESET and RESET Outputs

♦ Independent Watchdog Timer

♦ 1µA Standby Current

♦ Power Switching

20mA in Battery-Backup Mode

♦ On-Board Gating of Chip-Enable Signals;

2ns CE Gate Propagation Delay

♦ Voltage Monitor for Power Fail

♦ Backup-Battery Monitor

♦ ±1.5% Low-Line Threshold Accuracy 52mV above

Reset Threshold

Full-Featured µP Supervisory Circuit with

±1.5% Reset Accuracy

________________________________________________________________ Maxim Integrated Products

1

19-0433; Rev 4; 11/05

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

16

15

14

13

12

11

10

9

1

2

3

4

5

6

7

8

RESET

RESET

WDO

CE IN

GND

OUT

BATT

TOP VIEW

MAX807

CE OUT

WDI

LOW LINE

MR

BATT OK

PFI

PFO

BATT ON

DIP/SO/TSSOP

Pin Configuration

Ordering Information and Typical Operating Circuit appear at end of data sheet.

SuperCap is a registered trademark of Baknor Industries. MaxCap is a registered trademark of Cesiwid, Inc.