3 V, Voltage Monitoring Microprocessor Supervisory Circuits Data Sheet ADM706P/ADM706R/ADM706S/ADM706T, ADM708R/ADM708S/ADM708T FEATURES FUNCTIONAL BLOCK DIAGRAMS Precision supply voltage monitor 2.63 V (ADM706P, ADM706R, ADM708R) WATCHDOG WATCHDOG WATCHDOG TRANSITION WATCHDOG INPUT (WDI) TIMER 2.93 V (ADM706S, ADM708S) DETECTOR OUTPUT (WDO) 3.08 V (ADM706T, ADM708T) V RESET AND CC 100 A quiescent current WATCHDOG TIMEBASE 200 ms reset pulse width 70A MR Debounced manual reset input ( ) MR RESET, RESET GENERATOR (P = RESET) Independent watchdog timer V CC 1.6 second timeout (ADM706x) V * REF ADM706P/ADM706R/ Reset output POWER-FAIL ADM706S/ADM706T INPUT (PFI) POWER-FAIL Active high (ADM706P) OUTPUT (PFO) 1.25V Active low (ADM706R, ADM706S, ADM706T) Both active high and active low (ADM708R, ADM708S, * VOLTAGE REFERENCE = 2.63V (P/R), 2.93V (S), 3.08V (T) ADM708T) Figure 1. ADM706P/ADM706R/ADM706S/ADM706T Voltage monitor for power-fail or low battery warning RESET V Guaranteed valid with VCC = 1 V CC Superior upgrade for MAX706P/R/S/T, MAX708R/S/T 70A RESET MR RESET RESET APPLICATIONS GENERATOR V CC Microprocessor systems V * REF ADM708R/ADM708S/ Computers POWER-FAIL ADM708T INPUT (PFI) Controllers POWER-FAIL 1.25V OUTPUT (PFO) Intelligent instruments Critical microprocessor monitoring * VOLTAGE REFERENCE = 2.63V (R), 2.93V (S), 3.08V (T) Battery-operated systems Figure 2. ADM708R/ADM708S/ADM708T Portable instruments GENERAL DESCRIPTION The ADM706P/ADM706R/ADM706S/ADM706T and the The ADM706R, ADM706S, and ADM706T are identical except ADM708R/ADM708S/ADM708T microprocessor supervisory for the reset threshold monitor levels, which are 2.63 V, 2.93 V, and circuits are suitable for monitoring either 3 V or 3.3 V power 3.08 V, respectively. The ADM706P is identical to the ADM706R supplies. in that the reset threshold is 2.63 V. It differs only in that it has an active high reset output. The ADM706P/ADM706R/ADM706S/ADM706T provide power-supply monitoring circuitry that generate a reset output The ADM708R/ADM708S/ADM708T provide similar functio- during power-up, power-down, and brownout conditions. The nality as the ADM706R/ADM706S/ADM706T and only differ reset output remains operational with VCC as low as 1 V. in that a watchdog timer function is not available. Instead, an Independent watchdog monitoring circuitry is also provided. active high reset output (RESET) is provided in addition to the This is activated if the watchdog input has not been toggled RESET active low ( ) output. within 1.6 seconds. All parts are available in narrow 8-lead PDIP and 8-lead SOIC In addition, there is a 1.25 V threshold detector for power-fail packages. warning, low battery detection, or to monitor an additional power supply. An active low debounced MR input is also included. 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 19952014 Analog Devices, Inc. All rights reserved. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Technical Support www.analog.com Trademarks and registered trademarks are the property of their respective owners. 06435-001 06435-002ADM706P/ADM706R/ADM706S/ADM706T, ADM708R/ADM708S/ADM708T Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Power-Fail Reset ......................................................................... 10 Applications ....................................................................................... 1 Manual Reset ............................................................................... 10 Functional Block Diagrams ............................................................. 1 Watchdog Timer (ADM706x) .................................................. 10 General Description ......................................................................... 1 Power-Fail Comparator ............................................................. 11 Revision History ............................................................................... 2 Adding Hysteresis to the Power-Fail Comparator ................. 11 Specif icat ions ..................................................................................... 3 RESET Valid Below 1 V VCC ..................................................... 11 Absolute Maximum Ratings ............................................................ 5 Applications Information .............................................................. 12 ESD Caution .................................................................................. 5 Monitoring Additional Supply Levels ...................................... 12 Pin Configurations and Function Descriptions ........................... 6 Microprocessors with Bidirectional RESET ........................... 12 Typical Performance Characteristics ............................................. 8 Outline Dimensions ....................................................................... 13 Circuit Information ........................................................................ 10 Ordering Guide .......................................................................... 14 REVISION HISTORY 10/14Rev. C to Rev. D Changes to Pin 4 Description Table 3 ........................................... 6 Changes to Pin 4 Description Table 4 ........................................... 7 Changes to Ordering Guide .......................................................... 14 5/08Rev. B to Rev. C Changes to Applications Section .................................................... 1 Changes to Table 2 ............................................................................ 5 Changes to Table 3 ............................................................................ 6 Changes to Figure 8 .......................................................................... 7 Changes to Figure 16 ........................................................................ 9 2/07Rev. A to Rev. B Updated Format .................................................................. Universal Changes to Table 1 ............................................................................ 3 Updated Outline Dimensions ....................................................... 12 Changes to Ordering Guide .......................................................... 13 Rev. D Page 2 of 16