Patent ID: 6853323

Claim:
A differential voltage output digital-to-analog converter comprising: a plurality of current steering cells under control of a first and second coded word, jointly coupled at a first and second pair of output nodes, each of the cells comprising: a pair of current sources supplying a pair of input currents substantially equal in magnitude; a first and second differential input stage connected at the first pair of output nodes and in series between the pair of current sources, responsive to a corresponding bit of the first coded word and a corresponding bit of the second coded word, for steering the pair of input currents through the first pair of output nodes at which the pair of input currents are opposite in direction, and thus a pair of complementary currents is developed at the first pair of output nodes; and a first and second bypass unit connected at the second pair of output nodes and in series between the pair of current sources, for establishing a pair of dummy branches in parallel with the first and the second differential input stages when the corresponding bit of the first coded word and the corresponding bit of the second coded word are both in a predetermined state, whereby the pair of input currents are diverted to the second pair of output nodes; a first differential output operational amplifier comprising a noninverting and inverting input terminal connected to the first pair of output nodes, arranged in transimpedance output configuration to convert the total complementary currents into a differential voltage signal and to maintain the first pair of output nodes fixed at a predetermined voltage; and a second differential output operational amplifier comprising a noninverting and inverting input terminal connected to the second pair of output nodes, arranged in transimpedance output configuration to maintain the second pair of output nodes fixed at the predetermined voltage.