A 10-bit 250-MS/s binary-weighted current-steering DAC

This paper studies the impact of segmentation on current-steering digital-to-analog converters (DACs). Segmentation may be used to improve the dynamic behavior of the converter but comes at a cost. A method for reducing the segmentation degree is given. The presented chip, a 10-bit binary-weighted current-steering DAC, has >60 dB SFDR at 250 MS/s from DC to Nyquist. At 62.5 MHz signal frequency and 250 MS/s, we operated the device in 9-bit unary, 1-bit binary-weighted mode. The obtained 60 dB SFDR in this measurement demonstrates that the binary nature of the converter did not limit the SFDR. The chip draws 4 mW from a dual 1.5 V/1.8 V supply plus load currents. The active area is less than 0.35 mm² in a standard 1P-5M 0.18-μm 1.8-V CMOS process. Both INL and DNL are below 0.1 LSB.