The SY87725L is a single chip transceiver for data rates up to 2.5Gbps. On the receive side, it includes a complete clock recovery and data retiming circuit with an integrated 4-bit serial-to-parallel data converter. On the transmit side, it includes a synthesizer with an integrated 4-bit parallel-to-serial data converter. The S Y87725L r eceiver h as a s ynthesizer t hat generates an internal clock from an externally supplied TTL or PECL REFCLK that can be either 155.52MHz or 77.76MHz. This internal clock can be used by the clock recovery PLL if an absence of transitions on the input serial data stream prevents normal clock recovery. This enables it to provide a stable clock source in the absence of transitions on the incoming serial data stream.