Freescale's advanced RF power-handling technology, LDMOS, reduces cellular transmitter cost and power consumption

Freescale Semiconductor recently introduced its next-generation lateral diffusion metal oxide semiconductor (LDMOS) RF power transistors to meet the urgent need to reduce power consumption in cellular transmitters. Freescale's eighth-generation high-voltage (HV8) RF power LDMOS technology follows the company's consistent leading RF power transistor technology and is specifically designed to meet the stringent requirements of high data rate applications such as W-CDMA and WiMAX, as well as emerging standards such as LTE and multi-carrier GSM. The HV8 technology-based series of devices are optimized for operation in advanced power amplifier architectures, including Doherty used in conjunction with digital pre-distortion (DPD).

The primary benefit of Freescale's HV8 technology is improved operational efficiency, which helps reduce the total power consumption of base station systems and thus reduces operating costs. In addition, HV8 can also adapt to the more stringent operating environment requirements of advanced system architectures.

“Freescale has achieved significant performance improvements to keep LDMOS as the dominant technology for power amplifiers,” said Gavin P. Woods, vice president and general manager of Freescale’s RF business unit. “When used with advanced architectures or in legacy systems, our HV8 family is expected to achieve very high levels of system efficiency in next-generation transmitter designs.”

The first few products will have power levels between 100 W and 300 W. In addition, the HV8 products leverage and extend Freescale's low-cost molded package portfolio, offering great value and covering key frequency bands from 700 MHz to 2.7 GHz.

Transistors optimized for operation in the 900 MHz band are expected to be the first to benefit from HV8 RF Power LDMOS technology to effectively meet the stringent requirements of multi-carrier GSM systems. The Doherty reference design is optimized specifically for the MC-GSM market, demonstrating excellent efficiency and DPD correction performance even in some of the most stringent signal configurations.

HV8 Performance

As an example of HV8 performance, a symmetrical Doherty reference design (for multi-carrier GSM applications) using dual MRF8S9260H/HS transistors delivers 58.0 dBm (630W) peak power, 16.3 dB gain, 42.5% drain efficiency at an average output power level of 49.4 dBm (87W), and good broadband linearity. DPD evaluation also shows that this reference design is well calibrated using six GSM carriers in signal bandwidths up to 20 MHz. Similar performance results are achieved with the RF8S9260H, MRF8S9170N, MRF8S9200N, and MRF8P9300H transistors.

Freescale's HV8 LDMOS platform effectively meets the cost, performance and reliability requirements of power amplifier manufacturers, demonstrating Freescale's commitment to being a leader in RF for communications systems.