A new low-power alarm circuit introduced by Motorola allows designers to simplify the interface between a sensor and the "alarm" level output to a piezoelectric horn, LED or other signaling function. The unit replaces a significant number of separate discrete devices presently used in many designs.

The new unit, type MC14600, provides a sensitive front end that interfaces between a sensor and driver, such as a horn output or LED. It also provides a low-battery detect circuit function with horn chirp and logic level output. It includes an integrated piezoelectric horn driver with oscillator and flashing LED output driver.

Motorola's new MC14600 series alarm IC simplifies the process of interfacing a sensor or any "alarm" level voltage to a piezoelectric horn and/or LED. The MC14600 is not just a horn driver, but a comprehensive signal conditioning and power watchdog system on a chip. It's easily configured, with a minimum of passives, to serve a wide range of applications and circuit configurations.

With an average supply current of only 9 uA, the MC14600 Alarm IC is ideally suited to battery operated products. The new alarm IC also features a high impedance on-chip FET input comparator and logic outputs for low battery and alarm detection. The alarm detect threshold can be easily established with two resistors. Typical applications include intrusion alarms, moisture or water ingress alarms, and toxic gas warning systems.

In addition, the MC14600 also incorporates a low battery trip point, set internally or externally, an integrated oscillator and piezoelectric horn driver, pulsed LED drive output, reverse battery protection, input protection diodes on the detect input and a distinctive horn "chirp" during low battery conditions.

This is the kind of product that will bring a smile to many designers' faces; saving all the interface hassles for the horn or LED driver, adding features, saving passives, saving design time, and at an easy-to-swallow price. Whoever had the idea for the MC14600 deserves a large pat on the back and Motorola need to be complimented for producing a part that will not make them rich -- by itself -- but will make them loved by a large group of designers. The low current consumption will guarantee early adoption. It will be interesting to watch which of the additional features manufacturers will offer in their products.