The VSC8113 is an ATM/SONET/SDH compatible transceiver integrating an on-chip Clock Multiplication Unit (PLL) for the high speed clock as well as a clock and data recovery unit (CRU) with 8 bit serial-to-parallel and parallel-to-serial data conversion. The PLL clock is used for serialization in the transmit direction (Mux). The recovered clock is used for deserialization in the receive direction (Demux). The demultiplexer contains SONET/SDH frame detection and recovery. The device provides both facility and equipment loopback modes and two loop timing modes. The part is packaged in a 100PQFP with integrated heat spreader for optimum thermal performance and reduced cost. The VSC8113 provides an integrated solution for ATM physical layers and SONET/SDH systems applications.