GENERAL DESCRIPTION

The SP8107 is a three channel laser diode driver specifically designed for high speed DVD-RW or DVD-RAM applications. It operates two grounded laser diodes (650nm for DVD and 780nm for CD) and features three input channels that allow setting of three different optical power levels. The first channel (IR) has lower gain (100mA/mA) and output current (up to 200mA) and is used as a read channel. The second (I2) and third (I3) channels have higher gain (250mA/mA) and output current (up to 250mA) and are used as write channels. Each write channel may be switched on/off at very fast switching speeds with TTL/CMOS logic level signals applied to EN2 and EN3 inputs - channels are enabled at low logic level and disabled at high logic level. Outputs of all channels are summed together and connected to one of the outputs IOUT A or IOUT B depending on logic signal at the input SELA. High logic level at SELA selects output IOUT A, while low logic level selects output IOUT B. Inputs IR, I2, and I3 are current-controlled with 200 ohm DC impedance but allow voltage control by using external limiting resistors.

FEATURES

• Three current controlled inputs with independent ENABLE/DISABLE

• Two selectable outputs for grounded laser diodes

• Output current up to 400mA (250mA per input channel)

• Independent swing for each output channel controlled by external resistor

• On-chip oscillator with resistor controlled frequency

• Single 5V power supply

• Common ENABLE and oscillator ENABLE inputs

• TTL/CMOS logic level control signals

• Small SSOP16 package

APPLICATION

• DVD-RAM with CD-RW capability

• DVD-RW with CD-RW capability

• Writable data storage optical devices