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Supervisory Circuits with Windowed
Watchdog and Manual Reset in 5-Lead SOT-23
Data Sheet
ADM8323/ADM8324
Rev. A Document Feedback
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FEATURES
Windowed watchdog, 8 timeout options
26 reset threshold options
2.5 V to 5 V in 100 mV increments
4 reset timeout options
1 ms, 20 ms, 140 ms, and 1120 ms (minimum)
Manual reset input
Open-drain or push-pull
RESET
outputs
Low power consumption
Specified over wide temperature range (−40°C to +125°C)
Qualified for automotive applications
5-lead SOT-23 package
APPLICATIONS
Automotive
Microprocessor systems
Computers
Controllers
Intelligent instruments
Portable equipment
FUNCTIONAL BLOCK DIAGRAMS
ADM8323
V
CC
V
CC
MR
GND WDI
RESET
RESET
GENERATOR
WINDOWED
WATCHDOG
DETECTOR
DEBOUNCE
V
REF
11802-001
Figure 1.
ADM8324
V
CC
MR
GND WDI
RESET
RESET
GENERATOR
WINDOWED
WATCHDOG
DETECTOR
V
REF
11802-002
DEBOUNCE
Figure 2.
GENERAL DESCRIPTION
The ADM8323/ADM8324 are supervisory circuits that monitor
power supply voltage levels and code execution integrity in
microprocessor-based systems. An on-chip watchdog timer checks
for activity within a preset timeout window. A reset signal can also
be asserted by an external push-button switch through a manual
reset input. The
RESET
output is either push-pull (ADM8323)
or open-drain (ADM8324).
A watchdog failure results in a low output on the
RESET
pin. A
failure can be triggered either by a fast watchdog error (watchdog
pulses too close together) or by a slow watchdog error (no watchdog
pulse within the timeout period). This effectively gives a window
to observe the watchdog pulse. The watchdog timeout is measured
from the last falling edge of the watchdog input (WDI). There are
eight different watchdog windows available, as shown in Table 5.
Each device is available in a choice of 26 reset threshold options
from 2.5 V to 5 V in 100 mV increments. There are also four reset
timeout options of 1 ms, 20 ms, 140 ms, and 1120 ms (minimum).
The ADM8323/ADM8324 are available in a 5-lead SOT-23
package and typically consume only 10 μA, making them suitable
for use in low power portable applications.
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