Cellular 4G/LTE Channel Industry News

Freescale Airfast RF power solutions for LTE and multi-standard BTS

To meet growing demand for cost-effective RF power solutions capable of supporting skyrocketing data rates, multiple wireless standards and increasing network complexity, Freescale Semiconductor introduces the first two products from its advanced Airfast RF power portfolio. The offerings are engineered to deliver industry-leading power density, signal bandwidth, linear efficiency and gain in cost-effective, small form-factor configurations.

“As the world’s wireless networks have grown more complex, so too have the requirements of the RF power market,” said Ritu Favre, vice president and general manager of Freescale’s RF Division. “Multiple modulation formats, expanding bandwidth and shrinking form factors call for a more comprehensive, system-level approach to RF power technology. Our newest Airfast products are designed with these paradigm shifts in mind.”

The new AFT09VP350N product is the industry’s first 48V LDMOS transistor designed exclusively for multi-carrier GSM and multi-standard macro cell applications operating in the 720 – 960 MHz frequency band. When used in a Doherty configuration, the device delivers 57 dBm (500W) of peak power using only a single transistor package, nearly doubling the power capability of other LDMOS solutions with a similar footprint. By comparison, many of today’s average 40W-60W power transmitters typically use two or three individually packaged devices to achieve this level of peak power.

In a Doherty circuit designed for the 920 – 960 MHz band, the AFT09VP350N achieves 50 percent efficiency at an average output power of 50 dBm (100W) with over 19dB gain, while meeting stringent multi-carrier GSM corrected linearity specifications. This efficiency is further enhanced by Freescale’s cost-effective, over-molded plastic OMNI packaging featuring ultra-low thermal resistance. The AFT09VP350N also demonstrates instantaneous signal bandwidth capability of up to 100 MHz, enabled by a 50 percent reduction in device drain-source capacitance measured on a per-watt basis.

On the opposite end of the power and frequency spectrum of the new Airfast family products is the 28V AFT26HW050GS LDMOS transistor. The product is designed specifically for wide instantaneous bandwidth micro/metro cell LTE applications between 2500–2700 MHz. Similar to the AFT09VP350N, the AFT26HW050GS contains two independently matched transistors within a single package in a Doherty-compatible configuration. In a Doherty circuit designed for the 2620-2690 MHz band, AFT26HW050GS delivers 47 dBm (50W) of peak power, more than 15.5 dB Doherty gain and 48 percent efficiency at 39 dBm (8W) average power. Under these conditions, the device demonstrates DPD correction to -54 dBc using a 20 MHz LTE test signal. Targeted for 5W-7W transmitters, this represents seven points efficiency improvement relative to previous Freescale LDMOS solutions and is the highest reported silicon Doherty efficiency in the industry at this frequency. Complementing the high gain and efficiency, the AFT26HW050GS also supports instantaneous signal bandwidth of over 100 MHz.  Additionally, the device is housed in a manufacturing-friendly, surface-mount air-cavity package enabling devices to be mounted on embedded coins or simple via arrays for thermal and electrical grounding.

System-level approach for next-generation RF power products

Airfast RF power solutions are designed to simultaneously meet the challenges of increased efficiency, peak power and signal bandwidth, while addressing the persistent pressure to reduce costs. The newest Airfast devices increase bandwidth two to three times over previous generations, enabling OEMs to simplify product portfolios, reduce system costs and create wideband, multi-standard amplifiers.

Underscoring the cost effectiveness of the 48V technology used in the AFT09VP350N, the product helps OEMs create next-generation transmitters with substantially fewer components. This part reduction, combined with the product’s low thermal resistance plastic package, offers the opportunity to shrink power amplifier size and cost, leading to smaller and lighter remote radio heads for wireless network operators. The AFT26HW050GS also optimizes cost efficiency via manufacturing-friendly, surface-mount air-cavity packaging. This configuration, together with substantial efficiency improvements, allows for weight and system cost reductions by eliminating the need for expensive copper plates or coins. Consequently, radios can be smaller, lighter and more cost-efficient.

Pricing and availability

The AFT09VP350N and AFT26HW050GS are planned for general sampling in Q2 2012, together with reference designs and other support tools. For sampling and pricing information, please contact a local Freescale sales office. Additional devices are planned throughout 2012, spanning an array of cellular bands and power levels. For more information on Freescale RF power LDMOS solutions, please visit www.freescale.com/RFpower.

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