Qorvo® announced a new family of drivers and transimpedance amplifiers (TIA) for the pulse amplitude modulation-4 (PAM4) optical networking standard. PAM4, based on 2-bit amplitude modulation, is being adopted by data centers to carry increasing data rates, from 25G to 400G.

Qorvo’s initial PAM4 family comprises three 28 GBd linear drivers (single and quad-channel) and two, single channel, linear TIAs. The drivers are in production, and the single channel TIAs will be available for sampling in April. According to the company, the modules provide high gain and linearity in a small footprint, with the industry’s leading power efficiency — within the range of 200 mW per channel. Depending on the function, the ICs are fabricated with GaAs, InP or SiGe technologies.

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PAM4 Drivers

  • The QPA4854 is a quad-channel, 28 GBd linear driver developed for 100G NRZ and 200G/400G CFP8 PAM4 applications. The driver has 30 GHz bandwidth with 14 dB gain and 200 mW per channel power consumption. It has single-ended inputs and outputs.
  • The QPA4994 is a quad-channel, 28 GBd linear driver, also intended for 100G NRZ and 200G/400G CFP8 PAM4 applications. This design has a differential input and single-ended output. The driver’s bandwidth is 30 GHz, and power consumption is 330 mW per channel.
  • The QPA4993 is a single-channel, 28 GBd linear driver for 100G SFP28 applications. The device has a differential input and single-ended output. Bandwidth is 30 GHz, and power consumption is 330 mW per channel.

Linear TIAs

  • The TGA4875 is a single channel TIA developed for 100G PAM4 and discrete multi-tone (DMT) networks; it has 36 GHz bandwidth and a transimpedance gain of 5400 Ω.
  • The QPA4876D is also single channel and is intended for 200G/400G PAM4 and DMT applications. The bandwidth is 32 GHz, and transimpedance gain is 6100 Ω.

Vladimir Kozlov, founder and CEO of LightCounting Market Research, said, “While the current ramp of 100G Ethernet in large data centers is dramatic, there is considerable interest in implementing the new Ethernet speeds, especially with PAM4 modulation.”

Qorvo plans to release additional quad-channel drivers and TIAs in late 2017, adding to the more than 3 million transmit modulator driver amplifiers and TIAs the company has shipped.

The company’s optical networking portfolio will be exhibited at the OFC conference, March 21 to 23, in Los Angeles. Information about Qorvo’s optical products is available at www.qorvo.com/optical.