In this paper, we report a 6.24-Gb/s wide-input-range serializer ASIC using fixed-data-rate scheme that can be used for long-haul optical transmission of various display standards. The serializer includes three clock-and-data-recovery circuits, de-multiplexers, a digital processing block, a phase-locked-loop, multiplexers, and optical front-end circuits. To eliminate the need for a wide-range phase-locked loop, the fixed-data-rate scheme is used. The ASIC produces 6.24-Gb/s serialized data from parallel input signals and, with them, drives a verticalcavity surface-emitting laser. The serializer ASIC occupies 3.45 mm 2 and consumes 151.7 mW.