A linear-in-dB VGA is fabricated in 0.18-pm CMOS technology. It is composed of three cascaded VGAs. Each of them is based on a conventional VGA and a proposed gain control circuit. To avoid devices parameters and temperature behavior on gain characteristics of VGA, a bias circuit is adapted to a proposed gain control circuit. The gain range of 73dB, the gain error of within rt2dB, the NF of 5dB are obtained at 380MHz by measurement, and the maximum current consumption is 6 mA under a single 1.8V power supply.

Abstract:We propose a novel multi-level pre-equalizer composed of multiple binary analog finite impulse response (FIR) filters. The performance was investigated using numerical simulation of a 20-Gb/s four-level pulseamplitude-modulation (4-PAM) multi-mode fiber (MMF) transmission system. The analog FIR filters were designed using 28 nm fully depleted silicon on insulator (FD-SOI) based complementary metal-oxide-semiconductor (CMOS) circuits. The simulated CMOS circuits successfully compensated the multi-level signals distorted by modal dispersion. The error vector magnitude (EVM) of the transmitted 4-PAM signals was improved from 40% to 9%. The proposed design scheme will enable cost-effective, lowpower analog FIR filters for multi-level pre-equalization. Keywords: equalization, pre-distortion, FIR filter, 4-PAM, multi-mode fiber, CMOS circuit Classification: Fiber-Optic Transmission for CommunicationsNyquist pulse-amplitude modulation (PAM) signaling for 100-Gbit/s/λ optical short-reach transmission," European Conference on Optical Communication (ECOC2014), P.

A way of large temperature coefficient on PTAT voltage generator is proposed. By stacking the proposed circuits, a PTAT voltage generator with large temperature coefficient can be realized. The PTAT voltage generator is analyzed by use of 4-terminal MOSFET model in subthreshold region based on the diffusion current. The temperature coefficient of measured value is compared with that of theoretical value.

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