This paper is a report on a high ESD breakdown-voltage InP HBT transimpedance amplifier IC for optical video distribution systems. To make ESD breakdown-voltage higher, we designed ESD protection circuits integrated in the TIA IC using base-collector/base-emitter diodes of InP HBTs and resistors. These components for ESD protection circuits have already existed in the employed InP HBT IC process, so no process modifications were needed. Furthermore, to meet requirements for use in optical video distribution systems, we studied circuit design techniques to obtain a good input-output linearity and a low-noise characteristic. Fabricated InP HBT TIA IC exhibited high human-body-model ESD breakdown voltages (±1000 V for power supply terminals, ±200 V for high-speed input/output terminals), good input-output linearity (less than 2.9-% duty-cycle-distortion), and low noise characteristic (10.7 pA/ averaged input-referred noise current density) with a -3-dB-down higher frequency of 6.9 GHz. To the best of our knowledge, this paper is the first literature describing InP ICs with high ESD-breakdown voltages.

A novel delta-sigma modulator that utilizes a resonant-tunneling diode (RTD) quantizer is proposed and its operation is investigated by HSPICE simulations. In order to eliminate the signal-to-noise-and-distortion ratio (SINAD) degradation caused from the poor isolation of a single-stage quantizer (1SQ), a three-stage quantizer (3SQ), which consists of three cascoded RTD quantizers, is introduced. At a sample rate of 10 Gsps (samples per a second) and a signal bandwidth of 40 MHz (oversampling ratio of 128), the modulator demonstrates a SINAD of 56 dB, which corresponds to the effective number of bits of 9.3.