Digital/analog converter with programmable gain

A digital/analog converter with programmable gain for converting a digital input signal (Dn) into an analog output signal, the digital/analog converter having:

• (a) a signal input for applying the digital input signal (Dn);
• (b) a reference current source for generating a reference current (Iref), the current intensity of the reference current output by the reference current source being adjustable via a setting terminal of the digital/analog converter;
• (c) a mirror circuit array which contains a plurality of current mirror circuits which mirror the generated reference current (Iref) with an associated current mirror ratio to form mirror currents and
• a controllable switching device, which switches through the mirror currents output by the current mirror circuits, in a manner dependent on the digital input signal (Dn) present at the signal input, to a summation current node for generating a summation current (Isum);
• and
• (d) a current/voltage converter for converting the generated summation current (Isum) into a corresponding voltage (UA), which is output as an analog output signal via an analog signal output of the digital/analog converter,
• wherein the reference current source comprises an operational amplifier having a non-inverting input, an inverting input and a signal output, a transistor having a gate connected to the output of the operational amplifier, and a controllable resistor network, which contains a plurality of resistors which can be switched via associated switches for altering the reference current (Iref), flowing through the resistor network, and wherein the switches of the resistor network are connected via setting line to the setting terminal of the digital/analog converter.