25-Gb/s clock and data recovery IC using latch-load combined with CML buffer circuit for delay generation with 65-nm CMOS

A 25-Gb/s half-rate clock and data recovery (CDR) IC using a current-mode logic (CML) buffer circuit with a latch load circuit for delay generation is presented. To achieve low-power operation of the CDR, the latch-load circuit for delay generation is combined with a CML buffer circuit, which provides a wide controllable delay range. This enable a reduction in the number of the CML circuits for delay generation used in the CDR IC. To confirm the validity of the proposed method, we fabricated a 25-Gb/s half-rate CDR IC with the 65-nm CMOS process. The power consumption of the proposed circuit is around half that of the conventional half-rate CDR circuit The area for the core circuits is 0.09 mm2, and the power consumption without output buffers is 96mW.