The circuit consists of a 12-bit serial-in/parallel-out shift register, a 12-bit DAC register, a 12-bit CMOS DAC and control logic. Serial data is clocked into the input register on the rising edge of the CLOCK pulse. When the new data word has been clocked in, it is loaded into the DAC register with the LD input pin. Data in the DAC register is converted to an output current by the D/A converter.