The EL6938 is a highly integrated
laser diode driver designed to support
multi-standard writable optical drives.
It accomplishes this by incorporating a waveform generator
wherein the diode currents and timing details can be
programmed before operation. The data input circuitry
inspects the NRZ serial data waveform and generates
programmed waveforms in recognition of 3, 4, 5, or 6 or
more clock periods of space changing to 3, 4, 5, or 6 or more
clock periods of mark, and vice versa.
The architecture allows reprogramming of the timers to
support different media, Blue, DVD, or CD standards, and
different speeds. The programming is accomplished through
a serial interface port. Two outputs are provided to support
dual-laser multi-standard optical heads. The clock and NRZ
inputs can be either standard CMOS or LVDS, selectable
through a program bit.