Very high-frequency log-domain bandpass filters

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-/spl mu/m 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.

[1]  E. Seevinck,et al.  Companding current-mode integrator: A new circuit principle for continuous-time monolithic filters , 1990 .

[2]  C. Enz,et al.  A 1.2 V BiCMOS class AB log-domain filter , 1997, 1997 IEEE International Solids-State Circuits Conference. Digest of Technical Papers.

[3]  G.W. Roberts,et al.  LC ladder-based synthesis of log-domain bandpass filters , 1997, Proceedings of 1997 IEEE International Symposium on Circuits and Systems. Circuits and Systems in the Information Age ISCAS '97.

[4]  C. Toumazou,et al.  Log-domain filters, translinear circuits and the Bernoulli cell , 1997, Proceedings of 1997 IEEE International Symposium on Circuits and Systems. Circuits and Systems in the Information Age ISCAS '97.

[5]  D. R. Frey.  Log domain filtering for RF applications , 1996 .

[6]  G. van Ruymbeke,et al.  Design of low-power and low-voltage log-domain filters , 1996, 1996 IEEE International Symposium on Circuits and Systems. Circuits and Systems Connecting the World. ISCAS 96.

[7]  G.W. Roberts,et al.  Balanced log-domain filters for VHF applications , 1997, Proceedings of 1997 IEEE International Symposium on Circuits and Systems. Circuits and Systems in the Information Age ISCAS '97.

[8]  Yannis Tsividis,et al.  Externally linear, time-invariant systems and their application to companding signal processors , 1997 .

[9]  S. Pookaiyaudom,et al.  State-space synthesis of oscillators based on the MOSFET square law , 1996 .

[10]  K. M. Adams,et al.  Phase-compensation in electronic gyrator circuits , 1968 .

[11]  Raimondo Caprio.  Precision differential voltage--current convertor , 1973 .

[12]  D. R. Frey,et al.  Log-domain filtering: An approach to current-mode fil-tering , 1993 .

[13]  G.W. Roberts,et al.  Effects of transistor nonidealities on log-domain filters , 1997, Proceedings of 1997 IEEE International Symposium on Circuits and Systems. Circuits and Systems in the Information Age ISCAS '97.

[14]  Gordon W. Roberts,et al.  Log-domain filters based on LC ladder synthesis , 1995, Proceedings of ISCAS'95 - International Symposium on Circuits and Systems.

[15]  Robert Fox,et al.  Practical design of single-ended log-domain filter circuits , 1997, Proceedings of 1997 IEEE International Symposium on Circuits and Systems. Circuits and Systems in the Information Age ISCAS '97.

[16]  R. H. Walden,et al.  A 3.2-GHz second-order delta-sigma modulator implemented in InP HBT technology , 1995, IEEE J. Solid State Circuits.

[17]  D. Frey.  On log domain filtering for RF applications , 1995, Proceedings of Bipolar/Bicmos Circuits and Technology Meeting.

[18]  A. C. van der Woerd,et al.  General current-mode analysis method for translinear filters , 1997 .

[19]  J. F. Duque-Carrillo,et al.  A general description of common-mode feedback in fully-differential amplifiers , 1990, IEEE International Symposium on Circuits and Systems.

[20]  Gordon W. Roberts,et al.  The design of log-domain filters based on the operational simulation of LC ladders , 1996 .

[21]  D. Frey.  Exponential state space filters: a generic current mode-design strategy , 1996 .