Analog Technologies Low Noise Constant Current Laser Driver
ATLS1A102
FEATURES
1
SDN
GND
2P5V
LISL
P5V
LPGD
LIO
12
11
10
9
8
7
Ultra Low Noise: <10µA*
High Current without Heat Sink: 1A
High Absolute Accuracy: <0.1%
High Stability: 100ppm/°C
Dual Modulation Ports: High/Low Speed
Low Drop Out Voltage: 1V
Complete Shielding
2
3
4
5
6
VPS
19.4
PGND
LDA
LDC
LISH
14.5
Figure 1 Pin Names and Locations
The controller has 2 types of mounting packages: through hole
and surface mount. The latter saves PCB space the controller
takes.
Compact Size
SMT Package Available
*Total RMS between 0.1Hz to 0.5MHz.
Figure 1 is the actual size top view of the ATLS1A102D,
which shows the pin names and locations. Its thickness is 5mm.
APPLICATIONS
SPECIFICATIONS
Driving diode lasers with low noise, including DPSSLs,
EDFAs, fiber lasers, diode laser modules, etc.
Maximum output current:
1A
Output current noise:
<10µA
DESCRIPTION
(0.1Hz to 0.5MHz RMS)
The ATLS1A102 is an electronic module designed for
driving diode lasers with up to 1A low noise current. The
output voltage is 1.5V to 4V when powered by a 5V power
supply.
Low speed current set voltage:
(on LISL pin)
0 to 2.5V
0 to 0.5V
High speed current set voltage:
(on LISL pin)
The ATLS1A102 has two input ports for modulating the
output current: one for low speed of up to 0.08Hz bandwidth
and the other high speed modulation of up to 300KHz. The
former is for CW (Continuous Wave) operation and the
latter is for modulated operation.
Low speed modulation cut-off frequency: 0.08Hz
High speed modulation cut-off frequency: 300KHz
Power supply voltage range:
Thermal resistance:
4.5V to 5.5V
A high stability low noise 2.5V reference voltage is
provided internally for setting the output current. This
reference can also be as the voltage reference for external
ADCs (Analog to Digital Converters) and DACs (Digital to
Analog Converters), which might be used for monitoring
and/or setting the laser current.
60°C/W (free air)
30°C/W (PCB mount)
Operating temperature:
−25°C to 85°C
OPERATION PRINCIPLE
Figure 2 is the block diagram of the controller.
The shut down pin can turn the controller electronically
without disconnecting the power supply.
SDN
VPS
There is an output port, LIO (pin 11), dedicated for
monitoring the laser current. It can be connected to an ADC
or a voltmeter.
1
10
9
100KΩ
100nF
PGND
LDA
GND
Linear
2
LISL
Low
Pass
Filter
Mode
4
8
The control loop is monitored in real time by an internal
circuit, to make sure that it works properly. The monitoring
result is sent to the LPGD node (pin 12). When this pin is
pulled up internally, it indicates that the loops works fine.
Driver
Laser
Diode
P5V
5
6
By default, the maximum output current is set to 1A. This
value can be altered by external circuit which is shown in
the application section.
LDC
LISH
Current
Sense
Control
Unit
7
The ATLS1A102 is packaged in a 6 sided metal enclosure,
which blocks EMIs (Electro-Magnetic Interferences) to
prevent the controller and other electronics from interfering
each other.
Figure 2 Block Diagram
550 E. Weddell Drive, Suite 4, Sunnyvale, CA 94089, U. S. A. Tel.: (408) 747-9760, Fax: (408) 747-9770, Web: w w w .analogtechnologies.com
¬ Copyrights 2000 – 2005, Analog Technologies, Inc. All Rights Reserved. Updated on 3/29/2007.
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