AD9661A_15 Datasheet, PDF (1/12 Pages) Analog Devices – Laser Diode Driver with Light Power Control

a
Laser Diode Driver
with Light Power Control
AD9661A
FEATURES
and fall times are 2 ns to complement printer applications that
< 2 ns Rise/Fall Times
use image enhancing techniques such as pulse width modula-
Output Current: 120 mA
tion to achieve gray scale and resolution enhancement. Control
Single +5 V Power Supply
signals are TTL/CMOS compatible.
Switching Rate: 200 MHz typ
Onboard Light Power Control Loop
The driver output provides up to 120 mA of current into an
infrared N type laser, and the onboard disable circuit turns off
APPLICATIONS
the output driver and returns the light power control loop to a
Laser Printers and Copiers
GENERAL DESCRIPTION
The AD9661A is a highly integrated driver for laser diode appli-
cations such as printers and copiers. The AD9661A gets feed-
E _{back from an external photo detector and includes an analog}
feedback loop to allow users to set the power level of the laser,
T ^{and switch the laser on and off at up to 100 MHz. Output rise}
safe state.
The AD9661A can also be used in closed-loop applications in
which the output power level follows an analog POWER LEVEL
voltage input. By optimizing the external hold capacitor and
the photo detector, the loop can achieve bandwidths as high as
25 MHz.
The AD9661A is offered in a 28-pin plastic SOIC for
operation over the commercial temperature range (0°C to
+70°C).
FUNCTIONAL BLOCK DIAGRAM
E _TTL
DISABLE
TTL
PULSE
DISABLE
CIRCUIT
*13ns DELAY ON RISING
EDGE; 0ns ON FALLING
L _{PULSE2 TTL}
HOLD
CAL ^TTL
*_DELAY
VOLT
REF
V_REF
+5V
O POWER
LEVEL
ANALOG
V_{LEVEL SHIFT IN} + V_REF
LEVEL
SHIFT OUT
LEVEL
S 8
LEVEL
SHIFT IN
SHIFT
CIRCUIT
DAC
0–1.6V
V1
5pF
REF
3–120mA
1:10
I_OUT
LASER
DIODE
OUTPUT
AD9661A
PHOTO
DETECTOR
GAIN
50Ω
OB ^CGAIN
R_GAIN
POWER
MONITOR
ANALOG
V_REF
1:1
I_MONITOR
I_MONITOR
SENSE IN
1.0V
REV. 0
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
© Analog Devices, Inc., 1995
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
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