Low Voltage Supervisory Circuits with
Watchdog & Manual Reset in 5-Lead SOT-23
Preliminary Technical Data
Precision Low Voltage Monitoring down to 1.8V
9 Reset Threshold Options:
1.58V to 4.63V
140ms (Min) Reset Timeout
Watchdog Timer with 1.6s Timeout
Manual Reset Input
Reset Output Stages
Low Power Consumption (3µA)
Guaranteed Reset Output valid to VCC=1V
Power Supply Glitch Immunity
Specified from -40°C to +125°C
5-Lead SOT-23 Package
FUNCTIONAL BLOCK DIAGRAM
The ADM6821-ADM6825 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 9 reset threshold options
ranging from 1.58V to 4.63V. The reset and watchdog timeout
periods are fixed at 140ms (min) and 1.6s (typ), respectively.
The ADM6821-ADM6825 are available in 5-lead SOT-23
packages and typically consume only 3µA, making them
suitable for use in low power portable applications.
Table 1. Selection Table
Watchdog Timer Manual Reset
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