Preliminary Technical Data
FEATURES
Supervisory Circuits with Watchdog and
Manual Reset in 5-Lead SC70 and SOT-23
ADM823/ADM824/ADM825
FUNCTIONAL BLOCK DIAGRAM
ADM823
V
CC
V
REF
V
CC
RESET
GENERATOR
Precision 2.5 V to 5 V power supply monitor
7 reset threshold options: 2.19 V to 4.63 V
140 ms (min) reset timeout
Watchdog timer with 1.6s timeout (ADM823, ADM824)
Manual reset input (ADM823, ADM825)
Push-pull output stages:
RESET (ADM823)
RESET, RESET (ADM824/ADM825)
Low power consumption (3 碌A)
Guaranteed reset output valid to V
CC
= 1 V
Power supply glitch immunity
Specified over automotive temperature range
5-lead SC70 and SOT-23 packages
RESET
MR
DEBOUNCE
WATCHDOG
DETECTOR
04534-0-001
GND
WDI
Figure 1.
APPLICATIONS
Microprocessor systems
Computers
Controllers
Intelligent instruments
Portable equipment
GENERAL DESCRIPTION
The ADM823/ADM824/ADM825 are supervisory circuits
which monitor power supply voltage levels and code execution
integrity in microprocessor-based systems. As well as providing
power on reset signals, an on-chip watchdog timer can reset the
microprocessor if it fails to strobe within a preset timeout
period. A reset signal can also be asserted by means of an
external push-button, through a manual reset input. The three
parts feature different combinations of watchdog input, manual
reset input and output stage configuration, as shown in Table 1.
Each part is available in a choice of seven reset threshold
options ranging from 2.19 V to 4.63 V. The reset and watchdog
timeout periods are fixed at 140 ms (min) and 1.6s (typ),
respectively.
The ADM823/ADM824/ADM825 are available in 5-lead SC70
and SOT-23 packages and typically consume only 3 碌A, making
them suitable for use in low power portable applications.
Table 1. Selection Table
Output Stage
Part No.
ADM823
ADM824
ADM825
Watchdog Timer
Yes
Yes
鈥?/div>
Manual Reset
Yes
鈥?/div>
Yes
RESET
Push-Pull
Push-Pull
Push-Pull
RESET
鈥?/div>
Push-Pull
Push-Pull
Rev.PrB
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