RFMD casts GaN in starring cable TV role
RF Micro Devices is claiming the first GaN-based cable TV products, as it seeks to produce amplifier modules with the best efficiency, noise level and power output for this market.
“We re a huge player in cable TV currently,” explained Jeff Shealy, who was CEO of RF Nitro, the company that RFMD bought in 2001 to obtain its GaN technology. “It s very important for us to remain on the top in performance.”
The Greensboro, North Carolina, company is pairing its GaN HEMTs with GaAs PHEMTs in hybrid power doubler amplifier modules, targeted at use in cable TV infrastructure. Each module features two GaAs PHEMT and two GaN HEMT die.
These modules have already won places in reference designs that will see them used by original equipment manufacturers, RFMD says. The doubler amplifier modules are available immediately in volume and the company expects to begin shipping purchased modules this year, with initial orders already "in hand".
RFMD s GaN HEMTs exploit the higher power density of the semiconductor material to deliver highly efficient performance at the power levels used in cable TV.
Initial deployments should begin in the fourth quarter of the year, thanks to a design win with a cutting-edge CATV systems company based in Europe, while RFMD is also targeting US cable giants like Motorola and Cisco Systems.
The chip company claims that the modules deliver industry-leading carrier-to-intermodulation noise levels as low as 63 dB minimum and provide gain of over 20 dB. The amplifiers can also be driven at higher powers "“ with final power output increased by 2 to 3 dBmV over competing devices "“ meaning that fewer amplifiers are needed in overall systems.
The GaN HEMTs in these modules are made using the same process as RFMD s recently-announced high-power GaN HEMTs targeted at radar applications (see related stories).
Because of the importance of GaN in those military applications, Shealy is now vice president of Aerospace & Defense at the company, however GaN devices are being deployed all across RFMD s multimarket product group. The different groups can exploit economic GaN device production by piggybacking off of the company's existing high-volume GaAs power amplifier manufacturing.
“Our manufacturing is a tremendous advantage to us,” Shealy told compoundsemiconductor.net. “We use a high-performance silicon carbide platform, so we pay a little more in variable costs for the technology, but our fixed costs enable us to manufacture this technology in a very low-cost fashion.”
Although the cost of GaN devices remains high, the new hybrid amplifier is a relatively large component, where that additional cost can be better absorbed within the total bill of materials than for smaller, discrete devices.
The GaN HEMTs are produced on 3-inch SiC substrates, using the same line that it uses to manufacture GaAs devices on 4-inch wafers in RFMD s high-volume fab.