Datasheet

PIN
NAME FUNCTION
MAX690/
MAX692/
MAX694
MAX691/
MAX693/
MAX695
5 10 PFO
Output of the Power-Fail Comparator. It goes low when PFI is less than 1.3V. The
comparator is turned off and PFO goes low when V
CC
is below V
BATT
.
— 13 CE IN CE Gating Circuit Input. Connect to GND or V
OUT
if not used.
— 12 CE OUT
CE OUT goes low only when CE IN is low and V
CC
is above the reset threshold (4.65V
for MAX691 and MAX695, 4.4V for MAX693). See Figure 6.
— 5 BATT ON
BATT ON goes high when V
OUT
is internally switched to the V
BATT
input. It goes low
when V
OUT
is internally switched to V
CC
. The output typically sinks 25mA and can
directly drive the base of an external PNP transistor to increase the output current
above the 50mA rating of V
OUT
.
— 6 LOW LINE
LOW LINE goes low when V
CC
falls below the reset threshold. It returns high as soon
as V
CC
rises above the reset threshold. See Figure 6, Reset Timing.
— 16 RESET Active-High Output. It is the inverse of RESET.
— 8 OSC SEL
When OSC SEL is unconnected or driven high, the internal oscillator sets the reset time
delay and watchdog timeout period. When OSC SEL is low, the external oscillator input,
OSC IN, is enabled. OSC SEL has a 3µA internal pullup. See Table 1.
— 7 OSC IN
When OSC SEL is low, OSC IN can be driven by an external clock to adjust both the
reset delay and the watchdog timeout period. The timing can also be adjusted by
connecting and external oscillator to this pin. See Figure 8. When OSC SEL is high or
oating, OSC IN selects between fast and slow Watchdog timeout periods.
— 14 WDO
The Watchdog Output (WDO). WDO goes low if WDI remains either high or low for
longer than the watchdog timeout period. WDO is set high by the next transition at WDI.
If WDI is unconnected or at mid-supply, WDO remains high. WDO also goes high when
LOW LINE goes low.
MAX690–MAX695 Microprocessor Supervisory Circuits
www.maximintegrated.com
Maxim Integrated │ 5
Pin Description (continued)