Design of output buffer with low switching noise and load adaptability

摘要

A new CMOS output buffer with low switching noise and load adaptability is presented in this paper. By designing an innovative combination structure of two driving stages, the buffer can reduce switching noise and output ringing with no penalty on signal transmission speed. Furthermore, the buffer can automatically adjust the total driving capability in response to variation of loading condition, the load adaptive method is simple and effective without the necessity for a feedback circuit. The proposed buffer has been designed in a TSMC 90 nm CMOS process. Simulation results demonstrate that the proposed buffer achieves 4.1-53.5% improvements in ground bounce and 2.9-15.2% reductions in output ringing compared with those of the AC/DC buffer. Meanwhile, it reduces ground bounce by 6.5-17.6% and output ringing by 3.8-10.9% relative to the CSR buffer.