Low Voltage Supervisory Circuits with
Watchdog and Manual Reset in 5-Lead SOT-23
ADM6821/ADM6822/ADM6823/ADM6824/ADM6825
FEATURES
FUNCTIONAL BLOCK DIAGRAM
Precision low voltage monitoring
9 reset threshold options: 1.58 V to 4.63 V
140 ms (min) reset timeout
Watchdog timer with 1.6 sec timeout
Manual reset input
ADM6823
V
CC
V
CC
RESET
GENERATOR
RESET
V
REF
Reset output stages
DEBOUNCE
MR
Push-pull active-low
WATCHDOG
DETECTOR
Open-drain active-low
Push-pull active-high
Low power consumption (7 μA)
Guaranteed reset output valid to VCC = 1 V
Power supply glitch immunity
Specified from −40°C to +125°C
5-lead SOT-23 package
GND
WDI
Figure 1.
APPLICATIONS
Microprocessor systems
Computers
Controllers
Intelligent instruments
Portable equipment
GENERAL DESCRIPTION
The ADM682x are supervisory circuits that monitor power
supply voltage levels and code execution integrity in
Each part is available in nine reset threshold options, ranging
from 1.58 V to 4.63 V. The reset and watchdog timeout periods
are fixed at 140 ms (min) and 1.6 sec (typ), respectively.
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 parts
feature different combinations of watchdog input and manual
reset input and output stage configurations, as shown in Table 1.
The ADM682x are available in 5-lead SOT-23 packages and
typically consume only 7 μA, making them suitable for use in
low power, portable applications.
Table 1. Selection Table
Output Stage
RESET
Part No.
Watchdog Timer
Manual Reset
RESET
Push-Pull
-
ADM6821
ADM6822
ADM6823
ADM6824
ADM6825
Yes
Yes
Yes
Yes
-
Yes
Yes
Yes
-
-
Open-Drain
Push-Pull
Push-Pull
Push-Pull
-
Push-Pull
Push-Pull
Yes
Rev. 0
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