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.
Benefits and 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
Pin Configurations
appear at end of data sheet.
Typical Operating Circuit
+0.9V
V
CORE
V
CC
2
RSTIN
V
CC
1
RST
+1.8V
+3.3V
V
CC
(I/O)
RESET
I/O
NMI
GND
µP
V
DD
(MEMORY)
Applications
●
●
●
●
●
●
●
MAX6734
MAX6735
WDI
PUSHBUTTON
SWITCH
WDO
MR
GND
Multivoltage Systems
Telecom/Networking Equipment
Computers/Servers
Portable/Battery-Operated Equipment
Industrial Equipment
Printer/Fax
Set-Top Boxes
19-2629; Rev 8; 12/15
MAX6730–MAX6735
Single/Dual/Triple-Voltage μP Supervisory
Circuits with Independent Watchdog Output
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 4.3mW/°C above +70°C)
....347.8mW
8-Pin SOT23-8 (derate 5.6mW/°C above +70°C)
....444.4mW
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
Soldering Temperature (reflow)
Lead (Pb)-free packages.............................................+260°C
Package containing lead (Pb) .....................................+240°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.
Package Thermal Characteristics
(Note 1)
6 SOT23
Junction-to-Ambient Thermal Resistance (θ
JA
)
........230°C/W
Junction-to-Case Thermal Resistance (θ
JC
)
...............76°C/W
8 SOT23
Junction-to-Ambient Thermal Resistance (θ
JA
)
........180°C/W
Junction-to-Case Thermal Resistance (θ
JC
)
...............60°C/W
Note 1:
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer
board. For detailed information on package thermal considerations, refer to
www.maximintegrated.com/thermal-tutorial.
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 2)
PARAMETER
Supply Voltage
SYMBOL
V
CC
1,
V
CC
2
I
CC
1
Supply Current
I
CC
2
V
CC
1 < +5.5V, all I/O connections
open, outputs not asserted
V
CC
1 < +3.6V, all I/O connections
open, outputs not asserted
V
CC
2 < +3.6V, all I/O connections
open, outputs not asserted
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
CONDITIONS
MIN
0.8
15
10
4
3
4.625
4.375
3.075
2.925
2.625
2.313
2.188
1.665
1.575
TYP
MAX
5.5
39
28
µA
11
9
4.750
4.500
3.150
3.000
2.700
2.375
2.250
1.710
1.620
V
UNITS
V
www.maximintegrated.com
Maxim Integrated
│ 2
MAX6730–MAX6735
Single/Dual/Triple-Voltage μP Supervisory
Circuits with Independent Watchdog Output
Electrical Characteristics (continued)
(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
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