MAX705-MAX813L
Low-Cost, µP Supervisory Circuit
General Description
The MAX705-MAX708/MAX813L microprocessor (µP)
supervisory circuits reduce the complexity and number of
components required to monitor power-supply and battery
functions in µP systems. These devices significantly improve
system reliability and accuracy compared to separate ICs or
discrete components.
Applications
z Computers
z Controllers
z Intelligent Istruments
z Automotive Systems
z Critical µP Power Monitoring
The MAX705/MAX706/MAX813L provide four functions:
1)A reset output during power-up, power-down, and brownout
conditions.
2) An independent watchdog output that goes low if the
watchdog input has not been toggled within 1.6 seconds.
3)A 1.25V threshold detector for power-fail warning,
low-battery detection, or for monitoring a power supply other
than +5V.
Features
z µMAX Package: Smallest 8-Pin SO
z Guaranteed RESET Valid at Vcc=1V
z Precision Supply-Voltage Monitor
4.65V in MAX705/MAX707/MAX813L
4.40V in MAX706/MAX708
z 200ms Reset Pulse Width
4) An active-low manual-reset input.
z Debounced TTL/CMOS-Compatible Manual-Reset Input
The MAX707/MAX708 are the same as the MAX705/MAX706,
except an active-high reset is substituted for the watchdog
timer. The MAX813L is the same as the MAX705, except
RESET is provided instead of RESET.
z Independent Watchdog Timer
–
1.6sec Timeout
(MAX705/MAX706)
z Active-high Reset Output (MAX707/MAX708/MAX813L)
z Voltage Monitor for Power-Fail or Low-Battery Warning
Two supply-voltage monitor levels are available: The
MAX705/MAX707/MAX813L generate a reset pulse when the
supply
voltage
drops
below
4.65V,
while
the
MAX706/MAX708 generate a reset pulse below 4.40V. All four
parts are available in 8-pin DIP, SO and µMAX packages.
Typical Operating Circuit
Pin Configurations
TOP VIEW
()ARE FOR MAX813L ONLY.
Pin Configurations continued at end of data sheet.
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