Supervisory Circuits with Watchdog and Manual Reset in 5-Lead SC70 and SOT-23 Data Sheet ADM823/ADM824/ADM825 FEATURES FUNCTIONAL BLOCK DIAGRAM Precision 2.5 V to 5 V power supply monitor ADM823 7 reset threshold options: 2.19 V to 4.63 V V CC 140 ms (minimum) reset timeout V CC RESET Watchdog timer with 1.6 sec timeout (ADM823, ADM824) RESET GENERATOR V REF Manual reset input (ADM823, ADM825) Push-pull output stages MR DEBOUNCE RESET (ADM823) WATCHDOG DETECTOR RESET, RESET (ADM824/ADM825) Low power consumption: 5 A Guaranteed reset output valid to V = 1 V CC GND WDI Power supply glitch immunity Figure 1. Specified over automotive temperature range 5-lead SC70 and SOT-23 packages APPLICATIONS Microprocessor systems Computers Controllers Intelligent instruments Portable equipment GENERAL DESCRIPTION The ADM823/ADM824/ADM825 are supervisory circuits that These parts are available in a choice of seven reset threshold monitor power supply voltage levels and code execution integrity options ranging from 2.19 V to 4.63 V. The reset and watchdog in microprocessor-based systems. In addition to providing timeout periods are fixed at 140 ms (minimum) and 1.6 sec power-on reset signals, an on-chip watchdog timer can reset the (typical), respectively. microprocessor if it fails to strobe within a preset timeout The ADM823/ADM824/ADM825 are available in 5-lead SC70 period. A reset signal can also be asserted by an external push- and SOT-23 packages and typically consume only 5 A, making button, through a manual reset input. The three parts feature them suitable for use in low power, portable applications. different combinations of watchdog input, manual reset input, and output stage configuration, as shown in Table 1. Table 1. Selection Table Output Stage RESET Part No. Watchdog Timer Manual Reset RESET ADM823 Yes Yes Push-Pull ADM824 Yes Push-Pull Push-Pull ADM825 Yes Push-Pull Push-Pull Rev. D Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 20042013 Analog Devices, Inc. All rights reserved. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. 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Technical Support www.analog.com 04534-001ADM823/ADM824/ADM825 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Reset Output ..................................................................................9 Applications ....................................................................................... 1 Manual Reset Input .......................................................................9 Functional Block Diagram .............................................................. 1 Watchdog Input .............................................................................9 General Description ......................................................................... 1 Applications Information .............................................................. 10 Revision History ............................................................................... 2 Watchdog Input Current ........................................................... 10 Specifications ..................................................................................... 3 Negative-Going V Transients ................................................ 10 CC Absolute Maximum Ratings ............................................................ 5 Ensuring Reset Valid to V = 0 V ........................................... 10 CC ESD Caution .................................................................................. 5 Watchdog Software Considerations ......................................... 10 Pin Configurations and Function Descriptions ........................... 6 Outline Dimensions ....................................................................... 11 Typical Performance Characteristics ............................................. 7 Ordering Guide .......................................................................... 11 Circuit Description ........................................................................... 9 REVISION HISTORY 7/13Rev. C to Rev. D Change to Figure 16 .......................................................................... 9 Updated Outline Dimensions ........................................................ 11 10/10Rev. B to Rev. C Updated Outline Dimensions ....................................................... 11 Changes to Ordering Guide .......................................................... 11 5/08Rev. A to Rev. B Changes to General Description Section ...................................... 1 Changes to Table 4 ............................................................................ 6 Changes to Ordering Guide .......................................................... 11 2/07Rev. 0 to Rev. A Updated Format .................................................................. Universal Changes to Ordering Guide .......................................................... 11 10/04Revision 0: Initial Version Rev. D Page 2 of 12