High-Frequency Reference Design (HFRD-29.12) is a complete optical transceiver targeted for the small form-factor pluggable (SFP+) Multisource Agreement (MSA) market and other high-speed optical-transceiver applications. This design showcases the MAX3799 combination differential VCSEL driver and limiting amplifier. The MAX3799 limiting amplifier is optimized to provide standards-compliant sensitivity at data rates of either 1.25Gbps or 10.3125Gbps. The reference design is available with a variety of VCSEL (TOSAs) and receivers (ROSAs). Control of the MAX3799 is provided by the DS1874 SFP+ controller. The DS1874 interfaces to the MAX3799 with a 3-wire digital interface, and is used to regulate optical power, monitor functions, and control other MAX3799 settings. Communication with the SFP+ module is accomplished through the standard MSA I2C interface. The MAX3799 is a cost-effective solution for an SFP+ dual-rate transceiver. Combining the VCSEL driver and limiting amplifier into a single, 5mm x 5mm package reduces cost without compromising performance.