Electronically tunable PLL controller design using OTA

This paper presents an electronically tunable Proportional Integral (PI) controller employing Operational Transconductance Amplifiers (OTA) for use in a Phase Lock Loop (PLL). Bandwidth, time constants, phase margin, cross-over frequency, damping factor can all be electronically tuned by the use of OTA based PI controller. Parameter design equations based on OTA bias currents, and results are presented. OTAs have the advantage that they are free from input voltage linearity restriction and temperature dependence.