Low-voltage CMOS current-mode circuits: topology and characteristics

Abstract

The author presents an in-depth study of the topologies and characteristics of low-voltage CMOS current amplifiers. The input impedance, output impedance, bandwidth, noise performance, and dynamic range of current amplifiers are investigated both analytically and numerically. Several new circuit techniques specific to low-voltage CMOS current-mode circuits including pseudo-cascode, current–current feedback, inductive series peaking, and joint resistive/inductive series peaking and current–current feedback for bandwidth enhancement, output impedance boosting, and dynamic range improvement are proposed. To provide a quantitative comparison and to quantify the effect of these new circuit techniques, the current amplifiers investigated are implemented in TSMC 0.18 μm 1.8 V CMOS technology and analysed using Spectre from Cadence Design Systems with BSIM3V3 device models that count for both device parasitics and high-order effects. Simulation results are compared with those from analytical analysis.