SP8107 Datasheet, PDF (1/3 Pages) Sipex Corporation – Three Channel High Performance Laser Driver

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 ₁
I2
2
I3 ₃
RF
4
EN2 ₅
EN3
6
ENABLE ₇
OSCEN
8
16
15
14
SP8107 13
SSOP-16 ₁₂
11
10
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 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 I_OUT A or I_OUT B depending on logic signal at the input SELA. High logic level at SELA selects
output I_OUT A, while low logic level selects output I_OUT 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
I_OUT A and I_OUT 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
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