A linear transconductance cell with wide tuning range

摘要

A transconductance cell, comprising a pair of input transistors; and a tunable degeneration circuit having a first leg comprising a plurality of field effect transistors connected in series and a second leg comprising a plurality of field effect transistors connected in series, one end of the first leg being coupled to a first one of the input transistors and one end of the second leg being coupled to a second one of the input transistors, each of the field effect transistors having a gate configured to receive a tuning voltage, wherein the tunable degeneration circuit further comprises a tapped voltage divider network, each of a plurality of the taps being configured to apply the tuning voltage to a different pair of the field effect transistors, each of field effect transistors pairs comprising one of the field effect transistors from the first leg and one of the field effect transistors from the second leg, wherein the tanned voltage divider network is configured to generate a differential voltage between each of adjacent pair of the taps when the tuning voltage is applied to the tapped voltage divider network, the differential voltage being equal to the quiescent drain-to-source voltage of one of the field effect transistors.