Analog field programmable CMOS Operational Transconductance Amplifier (OTA)

This paper defines a approach to design the field programmable CMOS Operational Transconductance Amplifier (OTA). All the MOSFETs are replaced by the floating gate MOSFETs to make the OTA design programmable. The charge at the floating gate can be programmed after fabrication, based on Hot-e-injection and Fowler-Nordheim tunneling techniques which results in threshold voltage variation which in turn can modify circuit´s specifications. The high frequency small signal analysis of the design is prepared and specifications like output current, Transconductance, input impedance, output impedance and offsets of the design are re-derived in terms of threshold voltages of the MOSFETs. In order to achieve circuits AC and DC characteristics, the circuit is simulated using BSIM3 level 49 MOSFET models in T-spice 0.35um CMOS process. The simulated results shows 13 bit programming precision in transconductance, input impedance, output impedance, Temperature stability and dc offsets with respect to threshold voltage of respective MOSFETs.