GaN RF power transistors deliver 320W for basestation PAs, in plastic packages

June 06, 2016 // By Graham Prophet
MACOM has announced achieved efficiency of up to 79% for wireless basestations with high-power, plastic-packaged gallium nitride output transistors; the devices, rated for 320 W and 160 W come in rugged, low-cost plastic packaging that, the company says, widens the price/performance advantage versus legacy LDMOS parts.

In MACOM Technology Solutions’ MAGb series of GaN on Silicon power transistors designed for use in macro wireless basestations, and based on MACOM’s Gen4 GaN technology, the MAGb-101822-240B0P and MAGb-101822-120B0P power transistors are plastic TO-272-packaged. They provide 320 W and 160 W output peak power, respectively, in the load-pull system with fundamental tuning only, and cover all cellular bands and power levels within the 1.8 – 2.2 GHz frequency range. These transistors’ ability to operate over 400 MHz of bandwidth removes the need to use multiple LDMOS-based products, further optimizing cost and design efficiencies.


Plastic-packaged MAGb power transistors deliver power efficiency up to 79% – an improvement of up to 10% compared to LDMOS offerings – with only fundamental tuning across the 400 MHz RF bandwidth, and with linear gain of up to 20 dB. This, MACOM asserts, is a compelling alternative to ceramic-packaged devices without compromising RF performance or reliability – thermal behaviour is improved by 10% compared to ceramic-packaged MAGb offerings.


These power transistors enable the implementation of a simple symmetric Doherty amplifier design while maintaining excellent RF performance compared to lesser performing and complex asymmetric Doherty topologies imposed by LDMOS-based transistors. With MACOM’s MAGb series transistors, Doherty amplifier implementations show the same level of DPD friendliness as LDMOS-based solutions.


“DPD is critical to increase the efficiency of power amplifiers for 4G and 5G basestation applications and has a significant impact on network operators’ operating expenses and capital expenditures,” said Dr. Chris Dick, Chief DSP Architect at Xilinx. Xilinx has shown a demonstration in which its programmable devices carry out the signal processing for the DPD (digital pre-distortion) path, “[showcasing] the combined DPD capabilities of MACOM’s Gen4 GaN-based MAGb power transistors and Xilinx’s complementary DPD technologies on our 28 nm Zynq SoC and 16 nm UltraScale+ MPSoCs. This joint solution highlights the time-to-market advantages that can be achieved with a proven, interoperable DPD solution.”