AS1923 Product Brief Q u a d - Vo l ta g e M i c r o p r o c e s s o r S u p e r v i s o r y C i r c u i t 1 General Description 2 Key Features The AS1923 microprocessor supervisory circuit was designed to monitor up to four system supply voltages without the need for external components, and asserts a single reset if any of the monitored supply voltages drops below its reset threshold. The AS1923 features an active-low reset output that is asserted when any of the 4 monitored voltages are below their respective reset threshold. The reset output is open-drain with a weak internal pullup (10µA) to IN2. Reset remains low for a specified reset timeout period (120ms min) after all voltages have stabilized. The output is valid as long as the IN1 or IN2 input voltage remains >1V. Minimal external component requirements, small size, and wide temperature range (-40 to +85°C) greatly improves reliability compared to individual supervisory circuits or discrete components. A wide range of factory-trimmed threshold voltages are available to accommodate many different supply voltages/tolerances with minimal external component requirements. Factory-trimmed options are available for monitoring +5.0, +3.3, +3.0, +2.5, +1.8, and -5.0V supplies with -5% and/or -10% tolerances. The device is also available with one or two user-adjustable threshold options (via external resistor-divider network) if non-standard voltage thresholds are required. ! Simultaneous Quad-Voltage Monitoring ! Precision Factory-Trimmed Reset Threshold Options: +5.0, +3.3, +3.0, +2.5, +1.8, and -5.0V ! User-Adjustable Voltage Monitoring Threshold Options ! Low Supply Current: 55µA ! Open-Drain – AS1923A ! 10µA Current Source Pullup – AS1923B ! Reset Timeout Period: 120ms ! RESET Valid to IN1 = 1V or IN2 = 1V ! Immune to Fast INx Transients ! External Components not Required ! Guaranteed Performance: Operating Temperature Range = -40 to +85ºC ! 6-pin SOT23 package 3 Applications The AS1923 is available in an 6-pin SOT23 package. The device is ideal for portable and battery-powered systems, embedded controllers, intelligent instruments, automotive systems, critical CPU monitoring, and any multi-supply application. Figure 1. Application Diagram and Pinout Monitoring Voltage 1 Monitoring Voltage 2 Monitoring Voltage 3 Monitoring Voltage 4 4 IN4 1 6 IN3 IN1 5 IN2 AS1923 6 3 RESETN RESETN CPU GND 2 AS1923 5 IN2 IN3 1 RESETN 3 4 IN1 IN4 GND 2 www.austriamicrosystems.com Revision 1.00 1-2 AS1923 Product Brief Copyrights Copyright © 1997-2007, austriamicrosystems AG, Schloss Premstaetten, 8141 Unterpremstaetten, Austria-Europe. Trademarks Registered ®. All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. All products and companies mentioned are trademarks or registered trademarks of their respective companies. Disclaimer Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. austriamicrosystems AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with austriamicrosystems AG for current information. This product is intended for use in normal commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or lifesustaining equipment are specifically not recommended without additional processing by austriamicrosystems AG for each application. For shipments of less than 100 parts the manufacturing flow might show deviations from the standard production flow, such as test flow or test location. The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However, austriamicrosystems AG shall not be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise or flow out of austriamicrosystems AG rendering of technical or other services. Contact Information Headquarters austriamicrosystems AG A-8141 Schloss Premstaetten, Austria Tel: +43 (0) 3136 500 0 Fax: +43 (0) 3136 525 01 For Sales Offices, Distributors and Representatives, please visit: http://www.austriamicrosystems.com/contact www.austriamicrosystems.com Revision 1.00 2-2