ADM8691ARUZ Analog Devices Inc, ADM8691ARUZ Datasheet - Page 15

• Manufacturer Part Number: ADM8691ARUZ
• Description: IC,Power Supply Supervisor,CMOS,TSSOP,16PIN,PLASTIC
• Manufacturer: Analog Devices Inc
• Type: Battery Backup Circuitr

Specifications of ADM8691ARUZ

• Number Of Voltages Monitored: 1
• Output: Push-Pull, Push-Pull
• Reset: Active High/Active Low
• Reset Timeout: 35 ms Minimum
• Voltage - Threshold: 4.65V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ALTERNATE WATCHDOG INPUT DRIVE CIRCUITS
The watchdog feature can be enabled and disabled under
program control by driving WDI with a three-state buffer (see
Figure 28). When three-stated, the WDI input floats, thereby
disabling the watchdog timer.
This circuit is not entirely foolproof, and it is possible for a
software fault to erroneously three-state the buffer preventing
the ADM869x from detecting that the microprocessor is no
longer operating correctly. In most cases, a better method is to
extend the watchdog period rather than disable the watchdog.
WATCHDOG
CONTROL
STROBE
INPUT
Figure 28. Programming the Watchdog Input
WDI
ADM869x
ADM8690/ADM8691/ADM8692/ADM8693/ADM8694/ADM8695
Rev. A | Page 15 of 20
This can be done under program control using the circuit
shown in Figure 29. When the control input is high, the
OSC SEL pin is low and the watchdog timeout is set by the
external capacitor. A 0.01 μF capacitor sets a watchdog time-
out delay of 100 seconds. When the control input is low, the
OSC SEL pin is driven high, selecting the internal oscillator.
The 100 ms or the 1.6 s period is chosen, depending on which
diode is used, as shown in Figure 29. With D1 inserted, the
internal timeout is set at 100 ms; with D2 inserted, the timeout
is set at 1.6 seconds.
CONTROL
INPUT
Figure 29. Programming the Watchdog Input
1
D1
D2
1
HIGH = EXTERNAL TIMEOUT
LOW = INTERNAL TIMEOUT
OSC SEL
OSC IN
ADM869x