3-Channel Laser Diode Driver
with Oscillator
AD9662
Rev. SpA
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However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
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Tel: 781.329.4700
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Fax: 781.326.8703
2003 Analog Devices, Inc. All rights reserved.
FEATURES
Current controlled current source
with 3 input channels
Output current for Channel 3--315 mA
Output current for other channels--210 mA
Rise time/fall time of 0.8 ns
On-chip oscillator
Single 5 V power supply (10%)
Low output overshoot
Low power consumption
APPLICATIONS
CD-RW drives
DVD-RW, DVD+RW, MO drives
Laser diode current switching
GENERAL DESCRIPTION
The AD9662 is a laser diode driver for high performance CD
and DVD recordable drives. It includes three channels for three
different optical power levels: the read channel generates a
continuous output power level, whereas Channel 2 and
Channel 3 are used as write channels having 0.8 ns rise/fall
times. All channel currents are summed at the I
OUT
pin. Each
channel's output current is established by multiplying the
channel's gain by the channel's input current. The input current
for each of the input channels--INR, IN2, and IN3--can be set
either by using an external resistor that converts an input
voltage to a current or by directly using a current source.
An on-chip oscillator is provided to allow output current
modulation (to reduce laser mode hopping). Two external
resistors control the frequency and the amplitude swing of the
oscillator. The push-pull oscillator can swing up to 100 mA p-p
and has a frequency range of 200 MHz to 500 MHz.
For more information about the AD9662, contact Analog Devices,
Inc. via email at:
high_current_drivers.com@analog.com.
FUNCTIONAL BLOCK DIAGRAM
CHANNEL 3
CHANNEL 2
READ CHANNEL
OSCILLATOR
OUTPUT
I
OUT
ENABLE
R
S
R
F
04389-0-001
IN3
OUTEN3
IN2
OUTEN2
INR
OUTENR
OSCEN
Figure 1. AD9662 3-Channel Laser Diode Driver
AD9662
INR
1
IN2
2
GND
3
R
F
4
V
CC
V
CC
I
OUT
GND
16
15
14
13
04389-0-002
IN3
5
OUTENR
6
OUTEN2
7
OUTEN3
8
R
S
ENABLE
OSCEN
V
CC
12
11
10
9
Figure 2. QSOP-16 Pinout
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