A Compact-Sized 9-Bit Switched-Current DAC for AMOLED Mobile Display Drivers

An area-efficient 9-bit digital-to-analog converter (DAC) for application in current-mode active-matrix organic light-emitting diode mobile display drivers is presented. To reduce the chip size, the proposed DAC is realized with a novel switched-current architecture, which periodically receives digital bits one by one in series to perform single bit conversion. A high-performance current-mode S/H circuit is also suggested in order to increase the sampling speed and linearity of the DAC. The prototype 9-bit DAC occupies only 0.014 mm
²
per channel in a 0.35- μm CMOS process and achieves a 100-kS/s conversion rate at a static current of 10 μA under a 3.3-V supply. The measured maximum integral and differential nonlinearities are 1.6 and 0.8 LSB, respectively. Measured maximum interchannel current output deviations in the best and the worst chips are 15 and 35 nA, respectively.