DAC gain compensation for temperature and process variations

摘要

A compensation circuit and method cancels transmit digital-to-analog (DAC) gain variations in a wireless communication device. A transmit DAC produces an output current signal Iload load proportional to a reference current Iref which is inversely proportional to a load resistance Rload whereby the DAC output current signal Iload inversely tracks changes in the load resistance due to manufacturing process and temperature to cancel gain variations. The load resistor Rload and reference resistor Rref are preferably located on the same IC and made of the same material. The transmit DAC includes a current steering cell which receives the reference current Iref to produce the output current signal Iload in proportion of the reference current Iref.