A 120-MHz Broadband Differential Linear Driver With Channel Mismatch Cancellation and Bandwidth Extension for B-PLC Applications

Abstract

This paper introduces a broadband linear driver used in B-PLC system. The driver consists of two identical current-feedback amplifiers to realize a fully differential topology. A cross-current injection method between the noninverting and the inverting channels is proposed to reduce the even-order harmonics caused by the circuit mismatch. In addition, in order to increase the stability of the GBW to the changing load and maximize the bandwidth, a output stage implemented by a unit gain closed-loop amplifier is proposed to stabilize the open-loop gain of the overall circuit, meanwhile improve the linearity deteriorated by the crossover distortion. The proposed linear driver is fabricated in a SOI CBJT process and it can provide a maximum drive current of 500 mA under a 12-V power supply. The measurement results show that this linear driver is capable of driving a load of <inline-formula> <tex-math notation="LaTeX">$50~\Omega $ </tex-math></inline-formula> while achieving a output swing of <inline-formula> <tex-math notation="LaTeX">$16~{V_{pp}}$ </tex-math></inline-formula> with a second-order harmonic distortion (HD₂) of &#x2212;72 dBm and a third-order harmonic distortion (HD₃) of &#x2212;55 dBm. The bandwidth can reach 120 MHz. A complete in-system measurement also has been passed and the results show that the proposed driver chip can well meet the need of the B-PLC system.