Digital-to-analog converter with no offset-induced errors

摘要

A digital-to-analog converter network for converting a digital signal having a plurality of binary bits into an analog output signal includes an R-2R ladder array (8a), a reference current source (IREF), a plurality of switches (S1, S2, ...S9) associated with ladder sections of the ladder array (8a), and an operational amplifier (14). An equalization circuit (17) is operatively coupled to the inverting input of the operational amplifier (14) for selectively switching in a code-dependent impedance so that the effective output impedance of the ladder array (8a) remains substantially constant with binary codes of the digital input signal.