ADDITIONAL TECHNICAL
INFORMATION
SAFE OPERATING AREA
The Safe Operating Area of the FL500 laser diode driver is
determined by the amount of power that can be dissipated
within the output stage of the driver. If that power limit is
exceeded permanent damage can result.
D
o
noT
exceeD
The
s
afe
o
peraTing
a
rea
(soa). e
xceeDing
The
soa
voiDs
The
warranTy
.
Refer to the Wavelength Electronics website for the most
up-to-date SOA calculator for our products. The online tool
is fast and easy to use, and also takes into consideration
operating temperature.
www.teamwavelength.com/support/design-tools/soa-ld-calculator/
SOA charts are included in this datasheet for quick reference,
however we recommend you use the online tools instead.
An example SOA calculation for the FL500 for 1 W, 250 mA
for independent channels operation is shown in
V
S
= 5 Volts (Point C)
V
LOAD
= 2.5 Volts
I
LOAD
= 100 mA (Point B) V
DROP
= 5 - 2.5 = 2.5 Volts (Point A)
Unsafe Operating Area
Voltage Drop Across FL500 (V
S
- V
LOAD
) (
V
)
Maximum Current LDC1 or LDC2 (
A
)
FL500 Safe Operating Area
Independent Channels 1 W, 250 mA max
B
BB
A
C
25ºC Ambient
35ºC Case
Figure 11. FL500 Independent Channels SOA
!
Follow these steps to determine if the driver will be operating
within the SOA.
•
Refer to the laser datasheet to find the maximum voltage
(V
LOAD
) and current (I
LOAD
) specifications
•
Calculate the voltage drop across the driver: V
DROP
=
V
S
- V
LOAD
(V
S
is the power supply voltage)
• Mark V
DROP
on the X-axis, and extend a line upward
• Mark I
LOAD
on the Y-axis, and extend a line (Line BB) to
the right until it intersects the V
DROP
line
•
On the X-axis, mark the value of V
S
•
Extend a diagonal line from V+ to the intersection of the
V
DROP
and I
LOAD
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 FL500 will be outside of
the Safe Operating Area, the system must be changed so that
less power is dissipated within the driver. See Wavelength
Electronics Application Note
for information on shifting the Load
Line.
An example SOA calculation for the FL500 for 2 W, 500 mA
for parallel channels operation is shown in
where:
V
S
= 3 Volts (Point C) V
LOAD
= 2 Volts
I
LOAD
= 400 mA (Point B) V
DROP
= 3 - 2 = 1 Volts (Point A)
Figure 12. FL500 Parallel Channels SOA
B
BB
A
C
Unsafe Operating Area
FL500 Safe Operating Area
Parallel Channels 2 W, 500 mA max
Voltage Drop Across FL500 (V
S
- V
LOAD
) (
V
)
25ºC Ambient
35ºC Case
Maximum Current LDC1 or LDC2 (
A
)
© 2020
11
FL500 LASER DIODE DRIVER
