Preliminary Technical Data
FEATURES
Low Voltage Supervisory Circuits with
Watchdog & Manual Reset in 5-Lead SOT-23
ADM6821鈥揂DM6825
FUNCTIONAL BLOCK DIAGRAM
V
CC
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
Push-Pull Active-Low
Open-Drain Active-Low
Push-Pull Active-High
Low Power Consumption (3碌A(chǔ))
Guaranteed Reset Output valid to V
CC
=1V
Power Supply Glitch Immunity
Specified from -40擄C to +125擄C
5-Lead SOT-23 Package
ADM6821
V
CC
V
REF
RESET
GENERATOR
RESET
MR
DEBOUNCE
WATCHDOG
DETECTOR
GND
WDI
APPLICATIONS
Microprocessor Systems
Computers
Controllers
Intelligent Instruments
Portable Equipment
GENERAL DESCRIPTION
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 3碌A(chǔ), making them
suitable for use in low power portable applications.
Table 1. Selection Table
Part No.
ADM6821
ADM6822
ADM6823
ADM6824
ADM6825
Watchdog Timer
Yes
Yes
Yes
Yes
-
Manual Reset
Yes
Yes
Yes
-
Yes
Output Stage
RESET
-
Open-Drain
Push-Pull
Push-Pull
Push-Pull
RESET
Push-Pull
-
-
Push-Pull
Push-Pull
Rev. PrA
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