EL6836 pdf datasheet (Dual 4-C

The EL6836 is a high performance, dual output, laser driver for writeable DVD drives. The ENA pin enables the chip, while the SEL1 pin selects the IOUT pin. Various waveforms can be generated where the amplitude is determined by the currents flowing into IINR, IIN2, IIN3, and IIN4. The timing is determined by the signals at WEN2B, WEN3B, and WEN4B. The oscillator is enabled when OSEN is high. The amplified IINR current of the selected channel is enabled when the ENA pin is high. The total output current is the sum of the read current, the enabled write currents, and the oscillator current when enabled.
Usually a voltage DAC will drive a resistor that is in series with the IINR, IIN2, IIN3, and IIN4 input. The resistor allows the user to optimize the current gain for each channel.
WEN2B, WEN3B, and WEN4B are CMOS input pins with a 1.68V threshold. Output write current pulses are enabled when a low is applied to the WEN2B, WEN3B, or WEN4B pin. The write current will flow to the selected output. When SEL1 is high IOUT1 is selected. WENRB enables read and oscillator current when low.