Segmented D/A converter with enhanced dynamic range

摘要

A digital-to-analog converter having series-connected transistors forming high impedance current sources for respective segmented resistor strings. A series transistor forming a current sink for one resistor string presents a high output impedance by utilizing a negative feedback amplifier. The effects of a headroom resistor and an offset resistor in one resistor string are negated by configuring an output amplifier with appropriate gain resistors. A highly accurate D/A conversion can be achieved by utilizing all resistors of the main and sub-resistor strings with the same value.