Low Noise Constant Current Laser Driver
ATLS1A103
Analog Technologies
The controller has 2 types of packages: through hole mount and
surface mount. The latter saves PCB space the controller takes.
FEATURES
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
Complete Shielding
Figure 1 is the actual size top view of the ATLS1A103, which
shows the pin names and locations. Its thickness is 5mm.
SPECIFICATIONS
Maximum output current:
1A
Output current noise:
(0.1Hz to 0.5MHz RMS)
<10µA
Compact Size
Current set voltage range:
0 to 2.5V
SMT Package Available
*Total RMS between 0.1Hz to 0.5MHz.
Current limit set voltage range:
Modulation response bandwidth:
Minimum drop out voltage:
0 to 0.5V
350KHz
APPLICATIONS
0.3V + 0.5×Iout
(Iout: output current)
3.5V to 5.5V
−25°C to 85°C
Drive laser diodes with low noise, including DPSSL, EDFA,
fiber laser, direct diode lasers, etc.
DESCRIPTION
Power supply voltage range:
Operating case temperature:
OPERATION PRINCIPLE
The ATLS1A103 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. It uses two drivers, one is switch mode and the other
is linear mode. The former results in high power efficiency,
the latter keeps the output noise low and allows high
modulation speed.
Figure 2 is the block diagram of the controller.
The shut down control circuit accept signals from 3 sources:
external shut down, over-current and over-temperature signals.
When one of these signals is activated, the controller is shut
down. Only when all these 3 signals go up, the soft-start circuit
starts enabling the low noise driver.
When the maximum power consumed by the controller is
maintained to <1W, it does not require a heat sink to
operate.
The temperature sensor circuit turns down the controller upon
detecting the temperature to be 120°C.
The output current of the ATLS1A103 can be set linearly by
an input voltage or modulated by an external signal of up to
350KHz in bandwidth, resulting in 1µS rise and fall time.
The current limiter circuit monitors the output current and
shuts down the controller upon detecting the output current
exceeds the pre-set value.
A high stability low noise 2.5V reference voltage is
provided internally for setting the output current. This
reference can also be used as the voltage reference for
external ADCs (Analog to Digital Converters) and DACs
(Digital to Analog Converters).
When controller is shut down, the voltage reference is also shut
down.
100KΩ
SDN
VPS
1
12
11
The ATLS1A103 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.
10pF
PGND
GND
LISL
Shut-
2
3
down
& soft-
start
LDC
10
Voltage
reference
1
SDN
GND
2P5V
LILM
LIS
VPS
PGND
LDC
LDA
TMPO
LPGD
12
11
10
9
8
7
Laser
Diode
2
3
4
5
6
Temp.
sensor
circuit
19.4
LILM
Current
limiter
LDA
4
LIO
Current
sensor &
low noise
driver
9
8
7
TMPO
LPGD
LIS
5
6
14.5
LIO
Figure 1 Pin Names and Locations
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 – 2006, Analog Technologies, Inc. All Rights Reserved. Updated on 1/23/2006
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