News and New Products

Chip set simplifies analog cell-phone design

-- EDN, 6/6/1996

 A five-IC, 3.6V chip set from GEC Plessey Semiconductors integrates the functions of as many as 10 devices to implement an Advanced Mobile Phone System (AMPS) or Extended Total Access Communications System (ETACS) cellular phone. The only other ICs you need are external memory, an IF amplifier, and a power amplifier. A huge market still exists for this and similar analog systems, because AMPS dominates the US cellular-phone market, despite the encroachment of digital technologies, such as Global System for Mobile, IS-54, and IS-95. Although AMPS is an old technology, it meets the basic needs of millions of users and has a well-established coverage infrastructure.

The ACE9010 RF front-end IC combines a low-noise amplifier, mixer, and UHF VCO, alongside an ACE9020 receiver/transmitter-interface IC, which includes a prescaler, transmission up-converter, and VCO. The ACE9030 RF interface has a dual synthesizer, A/D and D/A converters for phone monitoring and management, and a crystal oscillator, which develops all reference and clock signals for the chip set. This oscillator features software-based automatic frequency control and replaces a more costly temperature-compensated voltage-controlled crystal oscillator. The ACE9040 audio processor comprises a compandor, filtering, connections for microphone and earpiece, and a dual-tone multiple-frequency generator for the audio baseband's transmitting and receiving paths. The ACE9050 system controller/data modem provides control and interface functions via its embedded microcontroller and 6 kbytes of RAM, sufficient for operational software, an interface to a keyboard and display, and external flash memory and EEPROM if necessary.

Each IC comes with management functions to minimize power consumption in any operating mode or situation. The chip set costs $28 (100,000).

—by Bill Schweber

GEC Plessey Semiconductors, Scotts Valley, CA. (408)438-2900, brent.wilkins@gpsemi.com