Comparing RF linearity of npn and pnp SiGe HBTs

Abstract

The RF linearity characteristics of complementary (npn + pnp) SiGe HBTs are investigated with respect to bias and frequency dependence, for the first time. The differences in distortion performance between npn and pnp SiGe HBTs are examined. Overall, at low bias currents (e.g., for minimum RF noise), both devices exhibit similar linearity performance and power gain, while for higher bias currents (e.g., for maximum gain), the pnp SiGe HBT offers advantages over the npn SiGe HBT. The linearity of both the npn and the pnp SiGe HBTs in common-emitter configuration improves as operating frequency rises.