Mainstream GaN

GaN: a breakthrough technology

If independent market research claims come true GaN product sales will exceed 300 Musd in 2014. This can only happen if GaN is made available through mainstream semiconductor companies, of which NXP is the first. So, what is it about GaN and RF power applications? Simply put, GaN makes a step increase in efficiency and power density performance over Si LDMOS in most applications. This can be quantified in the Johnson’s Figure of Merit (FoM) – a combination of significant RF performance variables that has a baseline for Si at 1 and leads to a FoM for GaN of 324. To put this into some context, GaAs, another commonly used compound material in RF, has a FoM of 1.44. Suffice to say, GaN truly represents a breakthrough technology.

Biasing

GaN products are termed High-Electron Mobility Transistors (HEMT), a name that captures one of the intrinsic benefits of GaN: the high electron drift velocity. These transistors are depletion-mode devices, that is, devices that are normally on, without the need for applying a gate bias. A negative gate bias will be needed to switch the transistors off. This biasing is not straightforward but at NXP we offer solutions rather than just components so already have a tried and tested bias circuit available and provide continuous application support through the life of the product.

High temperatures

A further advantage of GaN is that it is a very hard structure capable to withstand very high temperatures. NXP’s GaN transistors will be specified to a maximum temperature of 250 °C, compared to 225 °C for Si LDMOS. With such high temperatures there is a greater need to have packages capable of exploiting this feature. For this customers benefit from NXP’s 30 year legacy in RF power products, we are the only GaN supplier with such an industrial base that brings customers excellence in product reliability, cost and a high degree of confidence in the supply chain. As we like to say, this takes GaN mainstream.

1^st Generation NXP GaN products

The first generation NXP GaN products will be unmatched broadband amplifiers for use in applications requiring high RF performance across a wide range of frequencies up to 3.5 GHz. NXP’s 1^st generation GaN process is designed for products operating from a 50V supply voltage, delivering best-in-class efficiency and linearity. The products will use industry standard package footprints enabling customers to adopt NXP’s products into existing designs without changing the mechanical design. Next generation GaN devices from NXP will be super-efficient enabling a breakthrough in performance for the largest RF power market segment: cellular base-stations. In turn this technology will enable a break from linear amplifier topologies with the onset of switched mode power amplifier (SMPA) concepts. NXP’s commitment to exploit the technology in a full portfolio of products will also lead to products for higher frequency applications up to 10 GHz.

Table 1. Selection Guide Gen1 GaN Products.

Type	fmin (MHz)	fmax (MHz)	Pout (W)	VDS (V)	ηD (%)	Gp (dB)
CLF1G0060(S)‑10	0	6000	10	50	33.2	17
CLF1G0060(S)‑30	0	6000	30	50	59	15.9
CLF1G0035(S)‑50	0	3500	50	50	49	13
CLF1G0035(S)‑100	0	3500	100	50	59.5	13.9
CLF1G0035(S)‑100P	0	3500	100	50	50.1	12.7
CLF1G0035(S)‑200P	0	3500	200	50	43.5	11.5