PSI1250MP is a multi-protocol SERDES capable of operating at up to 12.5Gbps. PSI1250MP can provide interfaces for many applications operating from 9.5Gbps to 12.5Gbps. It also provides interfaces for applications with 1/2, 1/4 and 1/8 speed. Fig. 1 shows the simplified top-level block diagram of this module. At the RX side the serial input data goes through the input stage with linear equalization. The Clock and data recovery (CDR) circuit receives the data. It then extracts the clock, and provides the clock and the retimed data to the de-serializer. The de-serializer converts the serial data to 8, 10, 16, 20, 32 or 40 bit parallel data with corresponding rx-clk. A DFE (Decision Feedback Equalization) block has been implemented in this module, and for the cases where a higher jitter tolerance is required, it is enabled. A Loss Of Signal (LOS) detector detects if there are valid data at the input. At the TX side the serialized data goes through the output driver. Depending on the application, transmitter can serialize 8, 10, 16, 20, 32 or 40 bit parallel data to a differential serial output. To further improve the jitter performance there are programmable pre-emphasis capabilities at the transmitter output stage. In addition near end serial and far end parallel loopback are implemented to be able to test the module. To improve signal integrity the block also includes a calibration circuit providing control signals to make the transmitter output resistance and the receiver input resistance within 50Ω±5%.