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.

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 sup
ply other than +5V.
4) An active-low 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.

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.

Features

♦ µMAX Package: Smallest 8-Pin SO
♦ Guaranteed RESET Valid at VCC = 1V
♦ Precision Supply-Voltage Monitor
4.65V in MAX705/MAX707/MAX813L
4.40V in MAX706/MAX708
♦ 200ms Reset Pulse Width
♦ Debounced TTL/CMOS-Compatible
Manual-Reset Input
♦ Independent Watchdog Timer—1.6sec Timeout
(MAX705/MAX706)
♦ Active-High Reset Output
(MAX707/MAX708/MAX813L)
♦ Voltage Monitor for Power-Fail or Low-Battery Warning

Applications

Computers
Controllers
Intelligent Instruments
Automotive Systems
Critical µP Power Monitoring