A low power CMOS programmable gain amplifier employing positive feedback technique

摘要

Abstract This paper presents a low power CMOS programmable gain amplifier (PGA) utilizing a novel gm‐boosting technique to increase the maximum achievable DC gain. The structure increases the effective transconductance of the circuit without any additional elements. The gain enhancement is accomplished without increasing the power consumption. The variable gain function is achieved by varying the effective transconductance of the circuit and its output resistance. The proposed PGA achieves a wide gain range of 47.5?dB from 2.1 to 49.6?dB with a constant bandwidth. According to the post‐layout simulation results of the proposed circuit in 0.18‐μm TSMC CMOS process the bandwidth and the input referred noise voltage at the maximum gain are 11.3?MHz and 10.76?nV/sqrt (Hz), respectively. The second and third harmonic distortions of the proposed PGA at the minimum gain are less than ?72.4 and ?40.7?dB, respectively. The core circuit of proposed PGA draws only 164?μA from a 1.2‐V supply voltage occupying an area of 29?μm?*?26?μm.