THE MAGAZINE FOR COMPUTER APPLICATIONS
Circuit Cellar Online offers articles illustrating creative solutions
and unique applications through complete projects, practical
tutorials, and useful design techniques.

NEW PRODUCT NEWS—edited by Harv Weiner

Microprocessor Supervisory Circuit

The IMP1232LP is a microprocessor supervisory circuit with a selectable watchdog time-out period and threshold level. It monitors the 5-V power supply of a microprocessor and restarts if it becomes hung-up. The IMP1232LP saves 40% more power than competitive circuits, drawing 30 mA from the 5-V supply. Applications include network hubs, portable instrumentation, intelligent instrumentation, and industrial control, data acquisition, and automotive control systems.

Users can select the supply reset trip point level at 5% or 10%, corresponding to a 4.74-V threshold level. The 10% tolerance setting gives a 4.49-V threshold level. When the power supply voltage falls below the threshold level, the reset outputs activate for 250 ms after the supply returns to normal. For maximum system flexibility, the IMP1232LP watchdog time-out period can be set to 150 ms, 600 ms, or 1.2 s through the time delay control pin.

A debounced push-button reset input is included. When pulled low by a mechanical switch, the active-high and active-low reset outputs activate for 250 ms after the push-button is released.

IMP1232LP devices have an active-low and active-high reset output that support a variety of microcontroller and microprocessor architectures. The open-drain active-low reset uses an external pull-up resistor.

The IMP1232LP costs $0.70 for 1000. Devices are available in 8-pin SO, 8-pin DIP, 8-pin MicroSO, and 16-pin SO packages for commercial and industrial temperature ranges.

IMP Inc.
(408) 432-9100
Fax: (408) 434-0335
www.impweb.com

5-00

Circuit Cellar provides up-to-date information for engineers. Visit www.circuitcellar.com for more information and additional articles.
For subscription information, call (860) 875-2199, subscribe@circuitcellar.com or subscribe online. ęCircuit Cellar, the Magazine for Computer Applications. Posted with permission.