A current steering circuit includes a multitude of current stages each
including an associated current source transistor, and first and second
cascode transistors coupled in series with the associated current source
transistor. The first and second cascode transistors respectively receive
first and second reference voltages and are biased such that a voltage
appearing across any terminal pairs of the transistors is less than a
predefined value. Each current stage includes a first switch supplying
the current flowing through the transistors to a first resistive load in
response to a control signal, and a second switch supplying the current
to a second resistive load in response to a complement of the control
signal. An amplifier responsive to an analog multiplexer's output
provides a biasing voltage to each of the current stages. The analog
multiplexer supplies a different output voltage in response to different
counts of a counter.