DIGITAL TO ANALOGUE AND ANALOGUE TO DIGITAL CONVERTERS

摘要

A digital to analogue converter comprises a plurality of current sources (T0-Tn) and corresponding selection switches (D0-Dn) which connect the current sources to an output (3). In order to enable a constant capacitance to be presented at the output (3) regardless of the input digital code a plurality of dummy current sources (T0-Tn) which take the same form as the current sources (T0-Tn) are provided. The dummy current sources have associated selection switches (D0-Dn) which are operated by the logical inverse of the code applied to the current sources (T0-Tn).