Datasheet

Table 2. Input and Output Status In Battery Backup Mode
V
BATT
, V
OUT
V
BATT
is connected to V
OUT
via internal MOSFET.
RESET Logic-low
RESET Logic-high. The open circuit output voltage is equal to V
OUT
.
LOW LINE Logic-low
BATT ON Logic-high
WDI
WDI is internally disconnected from its internal pullup and does not source or sink current as long as its input
voltage is between GND and V
OUT
. The input voltage does not affect the source current.
WDO Logic-high
PFI The power-fail comparator is turned off and the power-fail input voltage has no effect on the power-fail output.
PFO Logic-low
CE IN
CE IN is internally disconnected from its internal pullup and does not source or sink current as long as its input
voltage is between GND and V
OUT
. The input voltage does not affect the source current.
CE OUT Logic-high
OSC IN OSC IN is ignored.
OSC SEL OSC SEL is ignored.
V
CC
Approximately 12µA is drawn from the V
BATT
input when V
CC
is between V
BATT
+100mV and V
BATT
- 700mV.
The supply current is 1µA maximum when V
CC
is less than V
BATT
- 700mV.
MAX690–MAX695 Microprocessor Supervisory Circuits
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