4-Channel LVDS Dual-Output

Laser Diode Driver with Oscillator

AD9664

Rev. SpA

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© 2004 Analog Devices, Inc. All rights reserved.

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

Independent TTL oscillator enable

150 mA minimum output current for Read Channel

325 mA minimum output current for Write Channel 1

250 mA minimum output current for Write Channel 2

150 mA minimum output current for Write Channel 3

Rise time/fall time of

≤0.8 ns

Low output overshoot

Low power consumption

Single 5 V power supply (±10%)

APPLICATIONS

DVD-R, DVD+R, DVD-RW, DVD+RW, DVD-RAM

supercombo drives

MO drives

Laser diode current switching

GENERAL DESCRIPTION

The AD9664 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 gener-

ates 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 OSCEN

pin is controlled by a TTL signal. All channels are summed at

the selected LD output pin where Write Channel 1 can contrib-

ute a minimum 325 mA maximum output current, and

Write Channel 2 and Write Channel 3 can contribute a mini-

mum of 250 mA and 150 mA, respectively. The level of the out-

put current is set by an external resistor, which converts this

voltage into a current at the xSET 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.

FUNCTIONAL BLOCK DIAGRAM

WRITE

CHANNEL 3

WRITE

CHANNEL 2

WRITE

CHANNEL 1

READ CHANNEL

OSCILLATOR

OUTPUT A

OSCEN

RDIS

W1DISN

W1DIS

W1SET

W2DISN

W2DIS

W2SET

W3DISN

W3DIS

W3SET

RSET

OUTPUT B

LD1

LD2

FADJ1 FADJ2 AADJ1 AADJ2

INS

OUTSEL

ENABLE

Figure 1. 4-Channel LVDS Laser Driver Block Diagram

24

INS

23

LVDD

22

LD1

21

LD1

20

GND

19

LD2

18

LD2

17

LVDD

AD9664

LFCSP

5mm × 5mm

(Not to Scale)

Figure 2. 4-Channel LVDS Laser Driver Pin Configuration

For more information about the AD9664, contact Analog Devices

at high_current_drivers.com@analog.com.