SoC Shores Up Amplifier Linearity

Linearity is an important performance parameter for amplifiers in many modern communications systems, although many transistors tend to have nonlinear characteristics. A new system-on-chip (SoC) adaptive RF power amplifier linearizer (RFPAL) from Scintera Networks, model SC1894, can improve upon an amplifier's linearity when used in small cell sites or repeaters. In addition to dynamically improving the linearity, it can also increase the efficiency of a power amplifier, for a net savings in power usage. According to Davin Lee, Chief Executive Officer of Scintera, "The SC1894 expands Scintera's linearization platform to include new features commonly found in RF transmitter systems such as PA gate biasing, RF power measurements, and temperature sensor. With improved linearization over previous RFPAL generations and the addition of these new features, the SC1894 will enable designers to further reduce system cost, power consumption, size, and design cycle time. Scintera is ideally positioned to benefit from the accelerating deployment of cellular heterogeneous networks and from other markets with similar design challenges including microwave P2P, TV white space and digital terrestrial broadcast." Model SC1894 provides improved correction capabilities compared to earlier generations of the firm's RFPAL devices. It also provides new features, including temperature-compensated gate biasing, dual RF power measurement capability, and a temperature sensor. It also incorporates quad analog-to-digital converters (ADCs) and quad digital-to-analog converters (DACs) that can be used to measure the output of an RF reverse power detector on the drain current of the final stage of a power amplifier. The linearizer SoC supports Class A/AB or Doherty RF power amplifier designs of at least 0.25 W from 168 to 4200 MHz and signal bandwidths from 25 kHz to 60 MHz. It is housed in a standard 64-pin, 9 x 9 mm QFN package.