East Fishkill, N.Y. - IBM Corp. has begun shipping radio frequency power amplifiers fabricated with silicon germanium (SiGe) technology instead of gallium arsenide (GaAs), thus permitting more highly integrated circuits.
The company introduced the IBM 2022 TDMA (time-division multiple access) IS-54 power amplifier at 800 MHz; the IBM 2018 CDMA (code-division multiple access) IS-95, also at 800 MHz; and the IBM 2017 PCS CDMA IS-95 at 1,900 MHz. All three will be manufactured at IBM's Burlington, Vt., facility using IBM's SiGe-based BiCMOS 5AM 0.5-micron technology on 200-mm wafers, and eventually on 300-mm wafers. The parts are aimed at cell phones and other wireless products.
Bernard Meyerson, vice president of the Communications Resources and Development Center at IBM Microelectronics, said the parts offer a combination of enhanced passive-device performance, low cost and fast wafer build time. "This is a breakthrough in this product category," he said. "Some experts thought such chips couldn't be done in SiGe, but would have to be manufactured in gallium arsenide, which is more expensive." IBM overcame the disadvantage of silicon germani- um-its relatively poor reliability-by adding circuit-protection devices to prevent high-voltage standing-wave ratio.
Meyerson said the SiGe chips offer superior thermal conductivity and efficiency. They "run cooler" and last longer than GaAs, with no hot spots, he said. Also, compared with GaAs, the SiGe BiCMOS process enables mixed-signal integration, allowing designers to leverage the benefits of silicon. The chips offer on-chip bias control, and should eventually integrate the switch, coupler and other discrete functions into the power amplifier, according to IBM.
The IBM 2022 TDMA power amplifier is priced at $1.19 in quantities of 100,000. The IBM 2017 PCS CDMA, at $3.52, is available as a prototype, and the IBM 2018 CDMA, priced at $3.04, will be available as a prototype this month. Further analysis of the products is available at www.chipcenter.com/analog/products_700-799/prod766.htm.
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EETInfo No. 626