The EL6915 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 part also has an
IV amplifier with concurrent read and write sampling. The
gains of the IV amplifier are programmable, eliminating the
need for external potentiometers.
The architecture allows reprogramming of the timers to
support different media, DVD or CD standards, and different
speeds. The programming is accomplished through a serial
interface port. Two outputs are provided to support duallaser
multi-standard optical heads. The clock and NRZ
inputs can be either standard CMOS or LVDS, selectable
through a program bit.
The EL6915 operates on a 5V supply for the analog circuits
and a 3.3V supply for the digital circuits.