It is significant to increase the precision of reference voltages produced by the reference resistor ladder at the front-end of high-speed A/D converters.To suppress nonlinear errors caused by the loading effect on the resistor ladder

a kind of parallel resistor ladder with fewer resistors on each branch is proposed.The error distribution of reference voltages along the parallel resistor ladder is also given.Without any compensation circuit

obvious precision improvement of reference voltages is achieved in addition to another advantages of faster settling speed、strengthened driving capability and lower temperature sensitivity.Both detailed analysis and simulation results show that it is very suitable for the use in high-speed A/D converters such as flash、multi-step and folding architectures

etc.