The composite replica-tail-feedback (CRF) bias is proposed to prevent valid window from reducing due to variations of input common mode (CM) level. The CRF bias is applied to a differential static amplifier and a differential clocked receiver. They are fabricated with 0.1µm CMOS process and the supply voltage is 1.2V. When input CM level changes between 0.5V and 1.0V, the static amplifier features output CM level variations of ±2.3% and propagation delay variations of ±7.5% against each average. Under the same condition, the clocked receiver provides zero setup and 60pS hold, and the alterations of hold are 14pS.