A master-slave scheme to tune gain of transconductance amplifiers with high accuracy

A simple technique to make the gain of transconductance amplifiers temperature insensitive and to tune them with high precision over a wide adjustment range is described. The technique uses a master-slave approach. It can be used to implement constant bandwidth instrumentation amplifiers. Experimental results using commercial operational transconductance amplifiers (OTAs) are presented showing that the proposed technique allows gain control over almost three decades with absolute accuracy better than 0.1%. Considerations for a fully integrated implementation are discussed