AD9665ACPZ-REEL7 Datasheet, PDF (1/17 Pages) Analog Devices – 4-Channel, LVDS, Dual-Output, Laser Diode Driver with Oscillator

4-Channel, LVDS, Dual-Output,
Laser Diode Driver with Oscillator
AD9665
FEATURES
Dual, current-controlled output current sources with 4 input
channels
TTL-selectable output
Stable on-chip oscillators with independent frequency and
amplitude control
TTL- or LVDS-selectable write channel enables negative logic
Independent TTL oscillator enables positive logic
170 mA minimum output current for the read channel
510 mA minimum output current for Write Channel 1
330 mA minimum output current for Write Channel 2
165 mA minimum output current for Write Channel 3
950 mA typical total output current
Typical rise time/fall time of 0.8 ns
Low power consumption
Single 5 V power supply (±10%)
APPLICATIONS
DVD-R, DVD+R, DVD-RW, DVD+RW, DVD-RAM
supercombo drives
Magneto-optical (MO) drives
Laser diode current switching
GENERAL DESCRIPTION
The AD9665 is a laser diode driver for high performance CD-RW
and DVD recordable drives. It includes four channels for four
different optical power levels: the read channel generates a
continuous output power level, whereas Channel 1, Channel 2,
and Channel 3 can be used as write channels that can be
controlled with an LVDS or TTL interface. The WxDIS and
RDIS pins are active low logic. The OSCEN pin is controlled by
an active high TTL signal. All active channels are summed at
the output where Write Channel 1 can contribute at least
325 mA output current, and Write Channel 2 and Write
Channel 3 can contribute at least 250 mA and 150 mA,
respectively. The level of the output current is set by an
external resistor, which converts this voltage into a current
at the WxSET pin.
An on-chip oscillator is provided to allow output current
modulation and to reduce laser-mode hopping. Four external
resistors permit the setting of two distinct values for the
frequency and swing of the oscillator. The oscillator can output
up to 100 mA p-p of current (push-pull oscillator) with a
frequency range of 200 MHz to 500 MHz.
W3SET
W3DIS
W3DISN
FUNCTIONAL BLOCK DIAGRAM
WRITE
CHANNEL 3
W2SET
W2DIS
W2DISN
WRITE
CHANNEL 2
OUTPUT A LD1
W1SET
W1DIS
W1DISN
RSET
RDIS
WRITE
CHANNEL 1
READ CHANNEL
OUTPUT B LD2
OSCEN
OSCILLATOR
ENABLE
INS OUTSEL
F_ADJ1 F_ADJ2 A_ADJ1 A_ADJ2
Figure 1. 4-Channel, LVDS, Laser Driver Block Diagram
W3DISN 1
W3DIS* 2
GND 3
GND 4
W2DISN 5
W2DIS* 6
W1DISN 7
W1DIS* 8
AD9665
LFCSP
5mm × 5mm
(Not to Scale)
24 INS
23 _VDD
22 LD1
21 LD1
20 GND
19 LD2
18 LD2
17 V_DD
*TTL ACTIVE LOW
NOTES
1. THE EXPOSED PAD SHOULD BE CONNECTED TO GROUND.
Figure 2. 4-Channel, LVDS, Laser Driver Pin Configuration
Rev. E
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