The VSC7990 is a single +5V or -5.2V supply, 10.7Gb/s laser diode driver with direct access to the laser modulation and bias FETs. Laser bias and modulation currents are set by external components allowing precision monitoring and setting of the current levels. Clock and data inputs are differentially terminated to 50 and must be AC-coupled. The superlative edge-rate and drive current of the VSC7990 enables efficient design of an OC-192/STM-64 transmitter using directly modulated laser diodes. A two-chip OC-12 to OC-192 optical transmitter can be easily implemented using the VSC7990 and the VSC8171 10Gb/s MUX/CRU.