Aimed at CDMA and TDMA personal communications in the 1.8 to 2.0GHz frequency band, Ericsson Microelectronics launched a family of highly linear RF power transistors.

Supporting the new digital transmitters as well as traditional analogue ones, the range comprises of four devices. The most powerful part is the PTF10120, exhibiting a groundbreaking 120W minimum output power at 28V, while at the other end of the scale is the 12W PTF10043, making an ideal pre-driver. Also included in the range is the 30W PTF10035 and the 60W PTF10112.

The range employs LDMOS (Laterally Diffused Metal Oxide Semiconductor) technology to significantly improve RF performance. The gain figure is around 3dB higher than bipolar equivalents and stability is also superior. For example, for the PTF10112 power gain is typically 12ý0.3dB in the 1.93 to 1.99GHz PCN band.

Furthermore, class AB efficiency is higher - typically around 40%. As a result, heat dissipation is lower and so smaller heatsinks can be used.

Ericsson's CDMA/ TDMA transistors can be integrated into many different combinations to create custom-made line-ups of any power gain. All the parts are internally matched, thereby simplifying matters for circuit designers and reducing component count.

My, Ericsson have been busy with their LDMOS product developments. This is a family of parts that will gain immediate acceptance for 1.9 GHz base station design. They provide the designer with a wide flexibility for choice for any single site solution, with, for example, the pairing of the 12 W PTF10043 as a driver with the 120 W PTF10120 as a final in the most demanding of those sites. Most stations, however, will need less power and will opt for the lower 30 and 60 W parts. The linearity of these parts is quite awesome, which will allow the use of currently available DACs in the signal path to be operated wider in bandwidth than before. The savings in channel cost will be immense for every bandwidth extension that can be achieved.