A variable gain amplifier device controlled by a first gain control signal
comprises a gain controlled amplifier having a gain and including a
differential pair of first and second MOS type transistors configured to
operate in a weak inversion region; and a control signal converter
configured to convert the first gain control signal into a second gain
control signal, and supply the second gain control signal to the gain
controlled amplifier to exponentially vary the gain with respect to the
first gain control signal.