Out in Front: March 28, 1996

A half-duplex, 300-bps transceiver IC provides a complete spread-spectrum system in a 44-lead TQFP IC. Applications for the GJRF01 from Gran-Jansen include home automation; security systems; heating, ventilation, and air-conditioning control; and low-speed data-acquisition and medical-instrumentation systems. Typical range is 90m for line-of-sight operation and 20 to 40m indoors.

The device operates from 300 to 500 MHz; typical operation is 433.92 MHz. It includes a transmitter delivering a selectable 1 to 5 mW output into a 50 Ohms load, a receiver with -60-dBm sensitivity for a 20-dB S/N ratio, a PLL frequency synthesizer, a local oscillator, filters, a crystal oscillator, and other associated circuitry for 50-hop/sec, spread-spectrum operation.

A complete transceiver system requires the GJRF01 plus approximately 20 external—mostly passive—components, such as a VCO resonator, a varicap diode, a crystal, capacitors, inductors, and resistors. The interface to a local processor, which sets registers for frequency dividers, timer, power, and selective power-up, is via a three-wire serial connection. The IC requires 2.7 to 3.3V, consuming 25 mA in transmitting mode and 15 mA in receiving mode. The IC costs $31 (1000); an evaluation board is also available.
—by Bill Schweber

Gran-Jansen AS, Oslo, Norway, fax: +47 22 49 59 03; granjan@ oslonett.no.