General Description

The MAX6323/MAX6324 microprocessor (µP) supervi-

sory circuits monitor power supplies and µP activity in

digital systems. A watchdog timer looks for activity out-

side an expected window of operation. Six laser-

trimmed reset thresholds are available with ±2.5%

accuracy from +2.32V to +4.63V. Valid RESET output is

The RESET output is either push-pull (MAX6323) or

open-drain (MAX6324). RESET is asserted low when

reset input (MR) is asserted low. RESET remains assert-

threshold and MR is deasserted.

The watchdog pulse output (WDPO) utilizes an open-

drain configuration. It can be triggered either by a fast

timeout fault (watchdog input pulses are too close to

each other) or a slow timeout fault (no watchdog input

pulse is observed within the timeout period). The

watchdog timeout is measured from the last falling

edge of watchdog input (WDI) with a minimum pulse

width of 300ns. WDPO is asserted for 1ms when a fault

is observed. Eight laser-trimmed timeout periods are

available.

The MAX6323/MAX6324 are offered in a 6-pin SOT23

package and operate over the extended temperature

range (-40°C to +125°C).

Applications

Automotive

Industrial

Medical

Embedded Control Systems

Features

o Min/Max (Windowed) Watchdog,

8 Factory-Trimmed Timing Options

o Pulsed Open-Drain, Active-Low Watchdog Output

o Power-On Reset

o Precision Monitoring of +2.5V, +3.0V, +3.3V,

and +5.0V Power Supplies

o Open-Drain or Push-Pull RESET Outputs

o Low-Power Operation (23µA typ)

o Debounced Manual Reset Input

µP Supervisory Circuits with Windowed

(Min/Max) Watchdog and Manual Reset

________________________________________________________________ Maxim Integrated Products

1

GND

WDI

16

5

MAX6323

MAX6324

SOT23

TOP VIEW

2

34

RESET

MR

WDPO

19-1838; Rev 2; 2/03

*These devices are factory trimmed to one of eight watchdog-

timeout windows and one of six reset voltage thresholds. Insert

the letter corresponding to the desired watchdog-timeout window

(A, B, C, D, E, F, G, or H) into the blank following the number

6323 or 6324 (see Watchdog Timeout table). Insert the two-digit

code (46, 44, 31, 29, 26, or 23) after the letters UT for the desired

nominal reset threshold (see Reset Threshold Range table at end

of data sheet).

Note: There are eight standard versions of each device available

(see Standard Versions table). Sample stock is generally held on

standard versions only. Standard versions have an order incre-

ment requirement of 2500 pieces. Nonstandard versions have an

order increment requirement of 10,000 pieces. Contact factory for

availability of nonstandard versions.

Pin Configuration

Ordering Information

Typical Operating Circuit appears at end of data sheet.

RESET

OUTPUT

PIN-

PACKAGE

TEMP

RANGE

PART*

MAX6323_UT__-T

-40°C to +125°C 6 SOT23-6

Push-Pull

Open Drain

6 SOT23-6

-40°C to +125°C

MAX6324_UT_ _-T

WATCHDOG TIMEOUT*

SUFFIX

A

B

C

D

E

F

G

H

719

39

23

15

15

15

15

1.5

MAX

FAST

UNITS

ms

ms

ms

ms

ms

ms

ms

ms

SLOW

MIN

UNITS

ms

10

100

300

10

60

s

ms

47

82

1.3

s

*See Figure 1 for operation.

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.

Watchdog Timeout