A 16-bit D/A interface with Sinc approximated semidigital reconstruction filter and reduced number of coefficients

摘要

Due to components nonidealities, the analog reconstruction is the most difficult analog building block in a D/A converter. The paper presents a 16-bit D/A interface with a current driven semidigital filter and reduced number of coefficients. To optimise the number of coefficients an iterative method based on Sinc approximation has been used. With only 25 coefficients we get more than 50dB stopband rejection of noise. A differential solution is proposed to reduce the digital crosstalk and to increase the output swing. The D/A interface has been realised on chip in a 0.8µm CMOS 5V technology. S/N+THD measurements are provided.