19-2629; Rev 5; 3/09
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 -40°C to +85°C temperature range.
Features
♦
V
CC
1 (Primary Supply) Reset Threshold Voltages
from +1.575V to +4.63V
♦
V
CC
2 (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
V
CC
1 or V
CC
2 = +0.8V
♦
Push-Pull
RESET
or Open-Drain
RESET
Output
♦
Immune to Short V
CC
Transients
♦
Low Supply Current: 14μA (typ) at +3.6V
♦
Small 6-Pin and 8-Pin SOT23 Packages
MAX6730–MAX6735
Ordering Information
PART*
MAX6730UT_D_
-T
MAX6731UT_D_
-T
MAX6732UT_
_D_ -T
MAX6733UT_
_D_ -T
MAX6734KA_
_D_ -T
MAX6735KA_
_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 SOT23
6 SOT23
6 SOT23
8 SOT23
8 SOT23
Applications
Multivoltage Systems
Telecom/Networking Equipment
Computers/Servers
Portable/Battery-Operated Equipment
Industrial Equipment
Printer/Fax
Set-Top Boxes
Typical Operating Circuit and Pin Configurations appear at
end of data sheet.
*Insert
the threshold level suffixes for V
CC
1 and V
CC
2 (Table 1)
after “UT” or “KA.” For the MAX6730/MAX6731, insert only the
V
CC
1 threshold suffix after the “UT.” Insert the reset timeout
delay (Table 2) after “D” to complete the part number. For exam-
ple, the MAX6732UTLTD3-T provides a V
CC
1 threshold of
+4.625V, a V
CC
2 threshold of +3.075V, and a 210ms reset time-
out period. Sample stock is generally held on standard versions
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.
Devices are available in both leaded and lead(Pb)-free/RoHS-
compliant packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Single-/Dual-/Triple-Voltage µP Supervisory
Circuits with Independent Watchdog Output
MAX6730–MAX6735
ABSOLUTE MAXIMUM RATINGS
V
CC
1, V
CC
2, RSTIN,
MR,
WDI to GND .....................-0.3V to +6V
RST, WDO
to GND (open drain)...............................-0.3V to +6V
RST, WDO
to GND (push-pull) .................-0.3V to (V
CC
1 + 0.3V)
Input Current/Output Current (all pins) ...............................20mA
Continuous Power Dissipation (T
A
= +70°C)
6-Pin SOT23-6 (derate 8.7mW/°C above +70°C) ........696mW
8-Pin SOT23-8 (derate 8.9mW/°C above +70°C) ........714mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Junction Temperature ......................................................+150°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
CC
1 = V
CC
2 = +0.8V to +5.5V, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Supply Voltage
SYMBOL
V
CC
1,
V
CC
2
V
CC
1 < +5.5V, all I/O connections
open, outputs not asserted
I
CC
1
Supply Current
V
CC
2 < +3.6V, all I/O connections
open, outputs not asserted
I
CC
2
V
CC
2 < +2.75V, all I/O connections
open, outputs not asserted
L (falling)
M (falling)
T (falling)
S (falling)
V
CC
1 Reset Threshold
V
TH
1
R (falling)
Z (falling)
Y (falling)
W (falling)
V (falling)
4.500
4.250
3.000
2.850
2.550
2.250
2.125
1.620
1.530
4
3
4.625
4.375
3.075
2.925
2.625
2.313
2.188
1.665
1.575
11
9
4.750
4.500
3.150
3.000
2.700
2.375
2.250
1.710
1.620
V
V
CC
1 < +3.6V, all I/O connections
open, outputs not asserted
CONDITIONS
MIN
0.8
15
10
TYP
MAX
5.5
39
28
µA
UNITS
V
2
_______________________________________________________________________________________
Microcontroller MCU
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