The MAX696/MAX697 supervisory circuits reduce the
complexity and number of components required for
power-supply monitoring and battery-control functions
in microprocessor (µP) systems. These include µP reset
and backup-battery switchover, watchdog timer, CMOS
RAM write protection, and power-failure warning. The
MAX696/MAX697 significantly improve system reliability
and accuracy compared to that obtained with separate
ICs or discrete components.
The MAX696 and MAX697 are supplied in 16-pin packages
and perform six functions:
1) A reset output during power-up, power-down, and
brownout conditions. The threshold for this "lowline"
reset is adjustable by an external voltage-divider.
2) A reset pulse if the optional watchdog timer has not
been toggled within a specified time.
3) Individual outputs for low-line and watchdog fault
conditions.
4) The reset time may be left at its default value of
50ms, or may be varied with an external capacitor
or clock pulses.
5) A separate 1.3V threshold detector for power-fail
warning, low-battery detection, or to monitor a
power supply other than VCC.
The MAX696 also has battery-backup switching for
CMOS RAM, CMOS microprocessor, or other low-power
logic.
The MAX697 lacks battery-backup switching, but has
write-protection pins (CE-bar IN and CE-bar OUT) for CMOS
RAM or EPROM. In addition, it consumes less than 250
microamperes.
Key Features
Applications/Uses
Adjustable Low-Line Monitor and Power-Down
Reset
Power-OK/Reset Time Delay
Watchdog Timer—100ms, 1.6s, or Adjustable
Minimum Component Count
1µA Standby Current
Battery-Backup Power Switching (MAX696)
On-Board Gating of Chip-Enable Signals
(MAX697)
Separate Monitor for Power-Fail or Low-Battery
Warning
Notes: **This pricing is BUDGETARY, for comparing similar parts. Prices are in
U.S. dollars and subject to change. Quantity pricing may vary
substantially and international prices may differ due to local
duties, taxes, fees, and exchange rates. For volume-specific prices
and delivery, please see the price and availability page
or contact an authorized distributor.
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