Advanced SP8107 Three Channel High Performance Laser Driver 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 IR I2 I3 RF EN2 EN3 ENABLE OSCEN 1 16 2 15 3 14 4 5 SP8107 SSOP-16 13 12 6 11 7 10 8 9 Vcc Iout A GND RSA RSB Iout B SELA Vcc GENERAL DESCRIPTION The SP8107 is a three channel laser diode driver specifically designed for high speed DVD-RW or DVDRAM 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. An on-chip oscillator is used to reduce laser mode hopping in read mode. The frequency of this oscillator may be changed by an external resistor connected to the RF pin. Oscillator swing can be set separately for IOUT A and IOUT B outputs by two resistors connected to RSA and RSB pins respectively. The oscillator is enabled by high logic level at the OSCEN pin. Low logic level at the ENABLE pin disables the entire device. Supply current in disabled mode is below 100uA. Pins EN2 and EN3 have internal pull-up resistors. Pins ENABLE, OSCEN, and SELA have internal pull-down resistors. Rev. 09/05/03 SP8107 – Three Channel Laser Driver Copyright 2003 Sipex Corporation SIPEX RESERVES THE RIGHT TO MAKE CHANGES TO THIS DATASHEET. CALL FOR UPDATES: 1-978-667-8700. SIPEX CONFIDENTIAL, ADVANCED & PROPRIETARY. DO NOT DISTRIBUTE OR COPY page 1 of 3 Advanced SP8107 PIN ASSIGNMENTS Pin Number Pin Name Pin Function 1 2 3 4 5 IR I2 I3 RF EN2 Read Channel current controlled input Write Channel 2 current controlled input Write Channel 3 current controlled input Connection of an external resistor to GND to set oscillator frequency Write Channel 2 enable input with an internal pull-up resistor. Logic high or floating turns channel off. Write Channel 3 enable input with an internal pull-up resistor. Logic high or floating turns channel off. Common device enable input with pull-down resistor. Logic low or floating turns device off. Oscillator enable input with pull-down resistor. Logic low or floating turns oscillator off. Supply voltage. Bypass to GND with 0.1uF ceramic capacitor Output select input with pull-down resistor. Logic high selects output A, low or floating selects output B Output current source B for a laser diode Connection of an external resistor to GND to set oscillator swing at the output B Connection of an external resistor to GND to set oscillator swing at the output A 6 EN3 7 ENABLE 8 OSCEN 9 10 Vcc SELA 11 12 13 IOUT B RSB RSA 14 GND Ground pin 15 16 IOUT A Vcc Output current source A for a laser diode Supply voltage. Bypass to GND with ceramic capacitors 0.1 and 0.01uF in parallel BOARD LAYOUT AND GROUNDING To obtain the best performance from the SP8107, a printed circuit board with ground plane is required. Layout should ensure that analog signal lines (IR, I2, and I3) are separated as much as possible from digital and output power lines. Output power lines should be as short and wide as possible. High quality, low series resistance ceramic 0.1 and 0.01uF bypass capacitors should be used at the Vcc pins 9 and 16. These capacitors must be located as close to the pins as possible. The traces connecting the pins and the bypassing capacitors must be kept short and should be made as wide as possible. Rev. 09/05/03 SP8107 – Three Channel Laser Driver Copyright 2003 Sipex Corporation SIPEX RESERVES THE RIGHT TO MAKE CHANGES TO THIS DATASHEET. CALL FOR UPDATES: 1-978-667-8700. SIPEX CONFIDENTIAL, ADVANCED & PROPRIETARY. DO NOT DISTRIBUTE OR COPY page 2 of 3 Advanced SP8107 ORDERING INFORMATION Part number SP8107 Temperature range -40 to +850C Package Type 16-pin SSOP Rev. 09/05/03 SP8107 – Three Channel Laser Driver Copyright 2003 Sipex Corporation SIPEX RESERVES THE RIGHT TO MAKE CHANGES TO THIS DATASHEET. CALL FOR UPDATES: 1-978-667-8700. SIPEX CONFIDENTIAL, ADVANCED & PROPRIETARY. DO NOT DISTRIBUTE OR COPY page 3 of 3