Title :
Very high-frequency log-domain bandpass filters
Author :
El-Gamal, Mourad N. ; Roberts, Gordon W.
Author_Institution :
Microelectron. & Comput. Syst. Lab., McGill Univ., Montreal, Que., Canada
fDate :
9/1/1998 12:00:00 AM
Abstract :
A transistor-level all n-p-n differential log-domain integrator geared toward low-distortion very high-frequency (VHF) applications is proposed. Systematic design steps are suggested and used to realize second and higher order balanced bandpass filters, based on the method of operational simulation of doubly-terminated LC ladders. We discuss the special sensitivity of log-domain integrators to small dc biasing offsets, practical issues in the design of the input and output interface stages, and the effect of parasitic resistors and capacitors on high-frequency log-domain filters. Experimental results from a 0.8-μm BiCMOS implementation of a single-ended 220-MHz biquad and a balanced 130-MHz fourth-order bandpass filter are reported, with emphasis on their distortion characteristics
Keywords :
BiCMOS analogue integrated circuits; VHF circuits; band-pass filters; biquadratic filters; continuous time filters; electric distortion; integrating circuits; ladder filters; 0.8 micron; 130 MHz; 220 MHz; BiCMOS IC; DC bias offset; LC ladder; balanced filter; biquad filter; design; distortion; interface circuit; parasitic capacitor; parasitic resistor; simulation; transistor-level n-p-n differential log domain integrator; very high frequency log domain bandpass filter; Analog integrated circuits; Band pass filters; BiCMOS integrated circuits; Capacitors; Filtering; Microelectronics; Nonlinear distortion; Resistors; VHF circuits; Voltage;
Journal_Title :
Circuits and Systems II: Analog and Digital Signal Processing, IEEE Transactions on
