Multidecade BCD DAC uses resistors of only six values

摘要

A previous Design Idea uses a three-decade BCD (binarycoded-decimal) DAC to precisely set the output current of a current source (Reference 1). The circuit acts as a code-to-conductivity converter. The values of resistors of this DAC are staggered by powers of two within any of the decades, and the values of resistorsrnat corresponding bits of the decades are staggered by powers of 10. Thus, the circuit needs 12 values of resistors, ranging from 125Ω to 100 kΩ.