DSP-Driven Self-Tuning of RF Circuits for Process-Induced Performance Variability

Abstract

In the deep-submicrometer design regime, RF circuits are expected to be increasingly susceptible to process variations, and thereby suffer from significant loss of parametric yield. To address this problem, a postmanufacture self-tuning technique that aims to compensate for multiparameter variations is presented. The proposed method incorporates a ?response feature? detector and ?hardware tuning knobs,? designed into the RF circuit. The RF device test response to a specially crafted diagnostic test stimulus is logged via the built-in detector and embedded analog-to-digital converter. Analysis and prediction of the optimal tuning knob control values for performance compensation is performed using software running on the baseband DSP processor. As a result, the RF circuit performance can be diagnosed and tuned with minimal assistance from external test equipment. Multiple RF performance parameters can be adjusted simultaneously under tuning knob control. The proposed concepts are illustrated for an RF low-noise amplifier (LNA) design and can be applied to other RF circuits as well. A simulation case study and hardware measurements on a fabricated 1.9-GHz LNAs show significant parametric yield enhancement (up to 58%) across the critical RF performance specifications of interest.