© 2018
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LDTC2/2 LASER DIODE DRIVER AND TEMPERATURE CONTROLLER
SAFE OPERATING AREA CALCULATION
To determine if the LDTC controller is suitable for your
application and if it will be operating in the safe range,
consult the instructions for calculating the Safe Operating
Area online at:
Laser Diode Drivers:
www.teamwavelength.com/support/design-tools/soa-ld-calculator/
Temperature Controllers:
www.teamwavelength.com/support/design-tools/soa-tc-calculator/
If you have any questions about the Safe Operating Area
calculator, call the factory for free and prompt technical
assistance.
!
It is imperative that you verify the unit will
operate within the internal heat dissipation
Safe Operating Area (SOA).
Operating the controller outside the SOA
may damage or destroy the LDTC and/or
LOADS.
We recommend using the online SOA calculators rather than
the charts provided here. The online calculators take into
consideration operating temperature, heatsinks, and airflow.
Follow these steps to use the SOA Chart to determine if the
LDTC will be operating safely. SOA charts for the LDTC2/2
Series are shown in
• Determine the V
DD
supply voltage for the laser driver.
•
Refer to the laser datasheet to find the maximum voltage
(V
MAX
) and current (I
MAX
) specifications.
• Calculate the voltage drop across the controller:
V
DROP
= V
DD
– V
MAX
• Mark V
DROP
on the X-axis, and extend a line upward.
• Mark I
MAX
on the Y-axis, and extend a line to the right
until it intersects the V
DROP
line.
• On the X-axis, mark the supply voltage (V
DD
).
• Extend a diagonal line from V
DD
to the intersection of the
V
DROP
and I
MAX
lines; this is the Load Line.
• If the Load Line crosses the Safe Operating Area line at
any point, the configuration is not safe.
If the SOA calculator indicates the LDTC will be outside of the
Safe Operating Area, the system must be changed so that
less power is dissipated within the driver. See Application
Note
AN-LDTC01: The Principle of the Safe Operating Area
for information on shifting the Load Line.
After changing any of the parameters, recalculate the SOA
to make sure the controller will operate safely. If you have
questions, or run into difficulties calculating the SOA, contact
Wavelength Electronics for assistance.
The SOA chart must be examined for both the laser driver
and for the temperature controller.
12
10
8
6
4
2
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0
Voltage Across LDTC2/2 (V)
Current (A)
SAFE OPERATION
UNSAFE OPERATION
Figure 15. Laser Driver SOA Chart, LDTC2/2.
With heatsink and fan.
25
20
15
10
5
0
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
Voltage Across LDTC2/2 (V)
Current (A)
SAFE OPERATION
UNSAFE OPERATION
Figure 16. Temperature Controller SOA Chart, LDTC2/2.
With heatsink and fan.