Power-Supply Monitor with Reset
MAX700/MAX701/MAX702
Pin Description
PIN
MAX700
1
MAX701
1
MAX702
1
NAME
MR
FUNCTION
Input for Manual Pushbutton Reset. Has internal 5µA pullup. Low input activates the
RESET/RESET outputs.
The voltage-sense input when CTL = V
CC
. Its threshold is 1.29V. SENSE always
remains connected to the internal comparator. So, when V
CC
is being monitored
internally (CTL = GND), SENSE should be left open circuit.
Normally NOT used when voltage is monitored through V
CC
(CTL = GND). When
monitoring through SENSE (CTL = V
CC
), HYST allows hysteresis to be added,
reducing noise and spurious reset activity (Figure 3). HYST turns on 5µs before the
RESET/RESET outputs are activated, and its on-resistance to GND is typically 1kΩ.
Ground
Goes low when V
CC
falls below 4.65V, or when CTL = V
CC
on the MAX700 goes low
when SENSE falls below 1.29V.
Inverted Version of
RESET
When CTL = GND, V
CC
is monitored by the reset circuit. When CTL = V
CC
, V
CC
is ignored
and SENSE is monitored, allowing the threshold to be set with external resistors.
Chip Power and +5V Sensing Input (When CTL = GND on MAX700)
No Connection
2
—
—
SENSE
3
—
—
HYST
4
5
6
7
8
—
4
6
5
—
8
2, 3, 7
3
7
—
—
2
4, 5, 6, 8
GND
RESET
RESET
CTL
V
CC
N.C.
4
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