Datasheet

PIN
NAME FUNCTION
MAX705/MAX706 MAX707/MAX708 MAX813L
DIP/SO μMAX DIP/SO μMAX DIP/SO μMAX
1 3 1 3 1 3 MR
Manual-Reset Input triggers a reset pulse when
pulled below 0.8V. This active-low input has an
internal 250μA pullup current. It can be driven from a
TTL or CMOS logic line, as well as shorted to ground
with a switch.
2 4 2 4 2 4 V
CC
+5V Supply Input
3 5 3 5 3 5 GND 0V Ground Reference for all signals
4 6 4 6 4 6 PFI
Power-Fail Voltage-Monitor Input. When PFI is less
than 1.25V, PFO goes low. Connect PFI to GND or
V
CC
when not used.
5 7 5 7 5 7 PFO
Power-Fail Output goes low and sinks current when
PFI is less than 1.25V; otherwise PFO stays high.
6 8 — — 6 8 WDI
Watchdog Input. If WDI remains high or low for
1.6sec, the internal watchdog timer runs out and
WDO goes low (Figure 1). Floating WDI or connecting
WDI to a high-impedance three-state bu󰀨er disables
the watchdog feature. The internal watchdog timer
clears whenever reset is asserted, WDI is three
stated, or WDI sees a rising or falling edge.
— — 6 — — — N.C. No Connect
7 1 7 1 — — RESET
Active-Low Reset Output pulses low for 200ms when
triggered, and stays low whenever V
CC
is below the
reset threshold (4.65V in the MAX705 and 4.40V in
the MAX706). It remains low for 200ms after V
CC
rises above the reset threshold or MR goes from low
to high (Figure 3). A watchdog timeout will not trigger
RESET unless WDO is connected to MR.
8 2 — — 8 2 WDO
Watchdog Output pulls low when the internal
watchdog timer nishes its 1.6sec count and does
not go high again until the watchdog is cleared. WDO
also goes low during low-line conditions. Whenever
V
CC
is below the reset threshold, WDO stays low;
however, unlike RESET, WDO does not have a
minimum pulse width. As soon as V
CC
rises above
the reset threshold, WDO goes high with no delay.
— — 8 2 7 1 RESET
Active-High RESET Output is the inverse of RESET.
Whenever RESET is high, RESET is low, and vice
versa (Figure 2). The MAX813L has a RESET output
only.
MAX705–MAX708/MAX813L MAX705–MAX708/MAX813L
Low-Cost, μP Supervisory Circuits
www.maximintegrated.com
Maxim Integrated │ 5
Pin Description