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