A 5-Gb/s Automatic Gain Control Ampli fier With Temperature Compensation Chang Liu, Y ue-Peng Y an

Abstract

This paper presents an automatic gain control (AGC) amplifier with temperature compens ation for high-speed appli- cations. The proposed AGC consists of a folded Gilbert variable gain ampli fier (VGA), a dc offset canceller, inductorless post amplifiers, a linear open-loop peak detector (PD), an integrator, a symmetrical exponential voltage generator, and a compensation block for temperature stability. The novel temperature com- pensation scheme ensures the AGC stability and accuracy over 20 C–200 C by predicting the integrator biasing voltage based on the crucial blocks duplication technique. The proposed linear open loop PD combined with the linear-in-dB VGA manages t h ed B - l i n e a re r r o ro fl e s st h a n0 . 3d Bf o rt h er e c e i v e ds i g n a l strength indication (RSSI). The AGC chip is fabricated using a 0.13- m SiGe BiCMOS technology. Consuming a power of 72 mW from a 1.2-V supply voltage, the fabricated circuit exhibits a voltage gain of 40 dB and a 3-dB bandwidth of 7.5 GHz. With a2 1 pseudo-random bit sequenc e at 5-Gb/s, the measured peak-to-peak jitter is less than 40ps across the 20 C–200 C temperature range. The low lin ear-in-dB error and the wide operating temperature range ach ieving the high-speed data input signal indicate the suitability of the proposed techniques for high-speed AGC ampli fiers.