Implementing its proprietary ultrathin-silicon-on-sapphire (UTSi) CMOS, also known as UltraCMOS process, Peregrine Semiconductor has developed RF CMOS switches that have achieved higher speed with lower power consumption to give designers a new alternative. Designed to switch GSM handset antennas to the receive or transmit path, the new CMOS RF switches deliver insertion loss, isolation, and switching performance that is competitive to switches based on gallium arsenide (GaAs) process technology.
In addition, the CMOS process lends itself to higher integration. Consequently, the new CMOS RF switches integrate on-chip functions like driver/decoder, RF level shifter, negative voltage generator, and SAW protection circuits. Plus, unlike GaAs, the CMOS switches require a single positive voltage control. This eliminates the blocking capacitors and the diplexer, normally required with GaAs switches, thereby enabling the CMOS-based switch to be directly connected to the antenna of a GSM handset.
According to Peregrine's director of marketing Rodd Novak, UltraCMOS process uses a perfect insulating substrate to overcome RF leakage, isolation and power-handling limitations of standard CMOS to compete with costly pseudomorphic high-electron-mobility transistor (pHEMT) GaAs and other similar complex semiconductor processes.
Using 0.5-micron UltraCMOS process, Peregrine has readied two types of 50-Ohm RF CMOS switches. While PE4263 is a single-pole, six-throw (SP6T) CMOS switch for quad-band GSM handset antenna switch module (ASM), the PE4261 is a single-pole, four-throw (SP4T) version in a flip-chip packaging for dual-band GSM handset antenna switch. According to Peregrine, flip-chip packaging enables handset makers to develop smallest, lowest cost ASMs with potential to achieve a profile of 1.0 µm total height. The use of flip-chip packaging reduces PCB area by a factor of nine when compared to conventional wire bonding, claims Peregrine.
Other features of PE4263 include three-pin CMOS logic control, high power of 41 dBm P1dB, high linearity of 65 dBm IP3 and monolithic integration of key elements. Likewise, the PE4261 offers two-pin CMOS logic control input. Both the new switches offer 1500 V ESD tolerance on all ports and have on-chip SAW overvoltage filter protection. Insertion loss is 0.55 dB at 900 MHz. Transmit-receive isolation is as high as 48 dB at 900 MHz and 40 dB at 1.9 GHz. Furthermore, the switches offer low harmonics (2f0 = -85 dBc, and 3f0 = -72 dBc at 35 dBm input power). The 2.6 V RF switches offer linear operation from 100 Mhz to 3000 MHz with fast switch settling time.
Available in die form (1.24 mm × 1.2 mm), the SP6T PE4263 costs $0.60 each, in 10,000 pieces. Likewise, in similar quantities, the SP4T PE4261 costs $0.52 each.
Peregrine Semiconductor Corp.