MAX6730 Datasheet, PDF (1/16 Pages) Maxim Integrated Products – Single-/Dual-/Triple-Voltage uP Supervisory Circuits with Independent Watchdog Output

19-2629; Rev 2; 1/03
Single-/Dual-/Triple-Voltage µP Supervisory
Circuits with Independent Watchdog Output
General Description
The MAX6730–MAX6735 single-/dual-/triple-voltage
microprocessor (µP) supervisors feature a watchdog
timer and manual reset capability. The MAX6730–
MAX6735 offer factory-set reset thresholds for monitor-
ing voltages from +0.9V to +5V and an adjustable reset
input for monitoring voltages down to +0.63V. The com-
bination of these features significantly improves system
reliability and accuracy when compared to separate
ICs or discrete components.
The active-low reset output asserts and remains asserted
for the reset timeout period after all the monitored volt-
ages exceed their respective thresholds. Multiple factory-
set reset threshold combinations reduce the number of
external components required. The MAX6730/MAX6731
monitor a single fixed voltage, the MAX6732/MAX6733
monitor two fixed voltages, and the MAX6734/MAX6735
monitor two fixed voltages and one adjustable voltage. All
devices are offered with six minimum reset timeout peri-
ods ranging from 1.1ms to 1120ms.
The MAX6730–MAX6735 feature a watchdog timer with
an independent watchdog output. The watchdog timer
prevents system lockup during code execution errors.
A watchdog startup delay of 54s after reset asserts
allows system initialization during power-up. The watch-
dog operates in normal mode with a 1.68s delay after
initialization. The MAX6730/MAX6732/MAX6734 provide
an active-low, open-drain watchdog output. The
MAX6731/MAX6733/MAX6735 provide an active-low,
push-pull watchdog output.
Other features include a manual reset input (MAX6730/
MAX6731/MAX6734/MAX6735) and push-pull reset out-
put (MAX6731/MAX6733/MAX6735) or open-drain reset
output (MAX6730/MAX6732/MAX6734). The MAX6730–
MAX6733 are offered in a tiny SOT23-6 package. The
MAX6734/MAX6735 are offered in a space-saving
SOT23-8 package. All devices are fully specified over
the extended temperature range (-40°C to +85°C).
Applications
Multivoltage Systems
Telecom/Networking Equipment
Computers/Servers
Portable/Battery-Operated Equipment
Industrial Equipment
Printer/Fax
Set-Top Boxes
Features
o V_CC1 (Primary Supply) Reset Threshold Voltages
from +1.575V to +4.63V
o V_CC2 (Secondary Supply) Reset Threshold
Voltages from +0.79V to +3.08V
o Adjustable RSTIN Threshold for Monitoring
Voltages Down to +0.63V (MAX6734/MAX6735 Only)
o Six Reset Timeout Options
o Watchdog Timer with Independent Watchdog Output
35s (min) Initial Watchdog Startup Period
1.12s (min) Normal Watchdog Timeout Period
o Manual Reset Input
(MAX6730/MAX6731/MAX6734/MAX6735)
o Guaranteed Reset Valid down to
V_CC1 or V_CC2 = +0.8V
o Push-Pull RESET or Open-Drain RESET Output
o Immune to Short V_CC Transients
o Low Supply Current: 14µA (typ) at +3.6V
o Small 6-Pin and 8-Pin SOT23 Packages
Ordering Information
PART*
MAX6730 UT_D_ -T
MAX6731 UT_D_ -T
MAX6732 UT_ _D_ -T
MAX6733 UT_ _D_ -T
MAX6734 KA_ _D_ -T
MAX6735 KA_ _D_ -T
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
6 SOT23-6
6 SOT23-6
6 SOT23-6
6 SOT23-6
8 SOT23-8
8 SOT23-8
*Note: Insert the threshold level suffixes for V_CC1 and V_CC2
(Table 1) after “UT” or “KA.” For the MAX6730/MAX6731, insert
only the V_CC1 threshold suffix after the “UT.” Insert the reset
timeout delay (Table 2) after “D” to complete the part number.
For example, the MAX6732UTLTD3-T provides a V_CC1 threshold
of +4.625V, a V_CC2 threshold of +3.075V, and a 210ms reset
timeout period. Sample stock is generally held on standard ver-
sions only (see the Standard Versions table). Standard versions
have an order increment requirement of 2500 pieces.
Nonstandard versions have an order increment requirement of
10,000 pieces. Contact factory for availability.
Typical Operating Circuit and Pin Configurations appear at end of data sheet.
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