1. A circuit for converting a digital input signal to an analog output signal indicative of the value of the digital signal, the digital signal including a plurality of bits grouped into a first group of M more significant bits and a second group of L less significant bits, the circuit comprising: first and second signal generating means for converting the first and second bit groups into corresponding first and second quantized analog signals; and amplifier means coupled to the first and second signal generating means and to an analog output node for producing an analog output signal at the analog output node, the amplifier means including a first differential transconductance stage which generates a first differential current responsive to a difference between the first quantized analog signal and a feedback signal from the analog output node, wherein the first differential current causes the amplifier means to produce an analog output signal having a first component substantially proportional to the value of the first bit group, and a second differential transconductance stage which generates a second differential current responsive to a difference between the second quantized analog signal and a reference signal, the second differential current combining with the first differential current in the amplifier means to offset the analog output signal by a second component substantially proportional to the value of the second bit group.