Digital-to-analog converter and a method for facilitating outputting of an analog output of predetermined value from the digital-to-analog converter in response to a digital input code

Abstract

A resistive DAC ( ) comprises a digital input port ( ) and an analog output port ( ) on which analog resistance output values are outputted in response to corresponding digital input codes on the input port ( ). A decoding and control circuit ( ) selects appropriate resistors (R ) to (RN) from a resistor chain ( ) for providing the analog resistance output of the analog output port ( ). A register ( ) stores a transfer coefficient in binary code which can be read through the input port ( ) and by which each digital input code should be multiplied in order to produce an analog resistance output of predetermined value. The transfer coefficient in the register ( ) takes account of variations in internal circuit parameters which causes the analog resistance outputs on the output port ( ) to be less than they would in an ideal resistive DAC.