Impedance Matching Networks for Current Output Integrated Circuits

This paper is aimed to solve the problem of wideband optimum power transferring between low impedance current output high speed integrated circuits and standard 50Ohm load. High amplitude current output circuits face some implementation obstacles, as an instance, in the TSMC 0.18 umCMOS process, in order to make the current carrying metal trace withstand to almost 80-120 mA, the trace should have characteristic impedance of about 6.25 ohm, and consequently,the output should be terminated by a load having the same value as current carrying trace owns which leads to impedancemismatch. This paper presents on-chip and off-chip impedance matching networks to eliminate this obstacle. Two off-chipcircuits (on 1mm FR4) and one integrated circuit are presented with design details and measurements. Matched system has shown almost sharp band-pass characteristics having a centerfrequency of 2.4 GHz with 800MHz bandwidth.

Keywords:

Broadband impedance matching , High speed current output ICs , Lumped network synthesis , Distributed network synthesis , Chebyshev bandpass filters , Edge coupled bandpass filters , Nonlinear optimization , Co-simulation