MAX6730–MAX6735
Single/Dual/Triple-Voltage μP Supervisory
Circuits with Independent Watchdog Output
General Description
The MAX6730–MAX6735 single/dual/triple-voltage micro-
processor (μP) supervisors feature a watchdog timer and
manual reset capability. The MAX6730–MAX6735 offer
factory-set reset thresholds for monitoring voltages from
+0.9V to +5V and an adjustable reset input for monitoring
voltages down to +0.63V. The combination 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 voltages
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 periods 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 watchdog 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 output
(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 -40°C to +85°C temperature range.
Applications
●● Multivoltage Systems
●● Telecom/Networking Equipment
●● Computers/Servers
●● Portable/Battery-Operated Equipment
●● Industrial Equipment
●● Printer/Fax
●● Set-Top Boxes
Benefits and Features
●● VCC1 (Primary Supply) Reset Threshold Voltages
from +1.575V to +4.63V
●● VCC2 (Secondary Supply) Reset Threshold Voltages
from +0.79V to +3.08V
●● Adjustable RSTIN Threshold for Monitoring Voltages
Down to +0.63V (MAX6734/MAX6735 Only)
●● Six Reset Timeout Options
●● Watchdog Timer with Independent Watchdog Output
• 35s (min) Initial Watchdog Startup Period
• 1.12s (min) Normal Watchdog Timeout Period
●● Manual Reset Input
(MAX6730/MAX6731/MAX6734/MAX6735)
●● Guaranteed Reset Valid down to
VCC1 or VCC2 = +0.8V
●● Push-Pull RESET or Open-Drain RESET Output
●● Immune to Short VCC Transients
●● Low Supply Current: 14μA (typ) at +3.6V
●● Small 6-Pin and 8-Pin SOT23 Packages
●● AEC-Q100 Qualified: MAX6734KATGD3/V+T,
MAX6734KALTD3/V+T
Pin Configurations appear at end of data sheet.
Typical Operating Circuit
+0.9V
VCORE
VCC2
VCC1
RSTIN
RST
MAX6734
MAX6735 WDI
PUSHBUTTON
SWITCH
MR
WDO
GND
+3.3V
+1.8V
VCC
(I/O)
RESET
VDD
(MEMORY)
I/O µP
NMI
GND
19-2629; Rev 9; 10/17
