Dual Processor Supervisors with Watchdog ADM13305 FEATURES FUNCTIONAL BLOCK DIAGRAMS Dual supervisory circuits ADM13305-18 ADM13305-25 Supply voltage range of 2.7 V to 5.5 V V ADM13305-33 DD Pretrimmed threshold options: 1.8 V, 2.5 V, 3.3 V, and 5 V 14k Adjustable 0.6 V voltage reference MR Maximum supply current of 40 A RESET 140 ms (minimum) reset timeout SENSE1 RESET R1 Watchdog timer with 1.6 sec (typical) timeout R2 LOGIC + TIMER RESET valid from V 1.1 V DD RESET SENSE2 RESET Push-pull RESET and outputs R3 R4 8-lead, narrow body SOIC package GND Temperature range: 40C to +85C 1.25V OSCILLATOR APPLICATIONS Supervising DSPs/microcontrollers TRANSITION WATCHDOG WDI Industrial and portable equipment DETECTION LOGIC + TIMER Wireless systems Notebook/desktop computers Figure 1. GENERAL DESCRIPTION ADM13305-4 The ADM13305 is a dual voltage supervisor designed to V DD ADM13305-5 monitor two supplies and provide a reset signal to DSP and 14k MR microprocessor-based systems. RESET There are five models available, all of which feature a combination SENSE1 RESET R1 of internally pretrimmed undervoltage threshold options for R2 LOGIC + TIMER monitoring 1.8 V, 2.5 V, 3.3 V, and 5 V supplies. There is also GND RESET an adjustable input option with an undervoltage threshold voltage of 0.6 V. SENSE2 The ADM13305-18, ADM13305-25, and ADM13305-33 models 0.6V have two internally fixed thresholds. The ADM13305-4 and OSCILLATOR ADM13305-5 offer one internally fixed threshold and one externally programmable threshold via a resistor string. See TRANSITION WATCHDOG WDI DETECTION LOGIC + TIMER the Ordering Guide for a list of all available options. RESET During power-up, is asserted when the supply voltage Figure 2 exceeds 1.1 V. The device then monitors the SENSEv input pins and holds the RESET output low as long as either of the SENSEv inputs remains below the rising threshold voltage, VIT+. Once the supplies monitored at the SENSEv inputs rise above As well as providing power-on reset signals, an on-chip watchdog their associated thresholds, the reset signal remains low for timer can reset the microprocessor if it fails to strobe within the the reset timeout period before deasserting. Subsequently, if a preset timeout period. A reset signal can also be asserted by an voltage monitored by the SENSEv pins falls below its associ- external push button through the manual reset input pin. RESET ated falling threshold, VIT, the output asserts. The The ADM13305 is available in an 8-lead, narrow body SOIC ADM13305 features both an active high RESET and an active package. The device operates over the extended industrial low RESET output. temperature range of 40C to +85C. Rev. 0 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 www.analog.com license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Fax: 781.461.3113 2007 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. 06922-001 06922-002ADM13305 TABLE OF CONTENTS Features .............................................................................................. 1 ESD Caution...................................................................................6 Applications ....................................................................................... 1 Pin Configuration and Function Descriptions ..............................7 General Description ......................................................................... 1 Typical Performance Characteristics ..............................................8 Functional Block Diagrams ............................................................. 1 Theory of Operation ...................................................................... 10 Revision History ............................................................................... 2 Input Configuration ................................................................... 10 Specif icat ions ..................................................................................... 3 Reset Output ............................................................................... 10 Timing Requirements .................................................................. 5 Watchdog Timer ......................................................................... 10 Switching Characteristics ............................................................ 5 MR Manual Reset ( ) .................................................................... 11 Functional Truth Table ................................................................ 5 Outline Dimensions ....................................................................... 12 Absolute Maximum Ratings ............................................................ 6 Ordering Guide .......................................................................... 12 Thermal Resistance ...................................................................... 6 REVISION HISTORY 8/07Revision 0: Initial Version Rev. 0 Page 2 of 12