A 12-bit 4GS/s DAC based on CMOS/InP heterogeneous integration

Abstract

This paper presents a 12-bit 4GS/s DAC in heterogeneous integration process of SMIC 0.18 $\mu$ m CMOS and 0.7 $\mu$ m InP HBT technology. The digital circuit is fabricated in CMOS technology to achieve high integration and low power consumption, while the analog circuit is composed by InP HBT technology with great high frequency performance. In this paper, a current-source switch structure is designed to reduce the variance of output impedance between ON and OFF states. Meanwhile, a deglitch circuit based on InP technology is added after the output of DAC to improve high frequency performance. The SFDR of the DAC at Nyquist-rate can reach more than 65dB.