A low-noise current reference circuitry includes a voltage source, a
current source, and a controller. The voltage source generates a
reference voltage. The current source provides a low-noise output current
in response to a control signal. The controller provides the control
signal based at least in part on the relative magnitudes of the reference
voltage and a voltage derived from the output current. A low-noise
voltage reference circuitry includes a reference voltage source, a
voltage source, and a controller. The reference voltage source generates
a reference voltage. The voltage source provides a low-noise output
voltage in response to a control signal. The controller provides the
control signal based at least in part on the relative magnitudes of the
output voltage and the reference voltage.