LDMOS
RF power transistors fabricated using the new LDMOS technology operate with higher gain and higher operating efficiencies than existing LDMOS devices, according to Philips. Fewer gain stages are needed in RF power amplifiers and less operating energy is wasted. Exceptional linearity means that these new transistors, even at high power levels, meet the ultra-low distortion requirements of multi-carrier W-CDMA and GSM EDGE base station amplifiers. The technology could also find use in transmitters for digital terrestrial TV systems.
The 0.6micron LDMOS technology achieves a 50% higher power density, a 6-8% higher W-CDMA efficiency and a 2dB power gain over 0.8micron technologies. A patented double gold metallisation and gold-gold wirebonding extends mean time to failure (MTTF) by 8-10 times that of conventional LDMOS devices, or alternatively allows operating junction temperatures up to 20C higher.
The first power transistors to use the new LDMOS technology are to be sampled in Q4 2003. Volume production will be ready in Q1 2004. The first device (BLF4G22-100) to be introduced will be a WCDMA transistor with 13.5dB gain, a gain flatness of 0.1dB (2.11-2.17GHz) and a 2-carrier WCDMA operating efficiency of 26% at a power output of 24W.
The fourth generation LDMOS technology will ultimately be applicable across all cellular frequency bands from 0.8-2.2GHz.
Philips' LDMOS roadmap shows plans to use a 0.18micron mainstream CMOS manufacturing process in the future.
