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WLD3393
PAGE 9
WLD3393-00400-K
STEP 5: ATTACH THE HEATSINK AND FAN
(optional for less than +5 V, 500 mA operation)
HEATSINK REQUIREMENTS.
The WLD3343 is designed to handle currents as high as 2.2 A. Attach
a heatsink -- Wavelength P/N WHS302 -- when the WLD3343 will operate between 500 mA and 1.0 A
output current. Attach a fan -- Wavelength P/N WXC303 [+5 VDC] or WXC304 [+12 VDC]) -- to the
heatsink for output currents exceeding 1.0 A. If using Wavelength accessories, refer to the WHS302,
WTW002, WXC303, and/or the WXC304 datasheets for assembly instructions.
FAN CONNECTIONS.
Connect the fan leads to the (+) and (-) fan power positions on the terminal
block and secure with a small
fl
at head screwdriver. The fan connects to the V
DD
supply, not V
S
, so care
must be exercised to ensure that the proper fan is selected, 5 VDC or +12 VDC, when using
dual power supplies. Optionally, for lower noise operation, the fan leads may be connected directly to
a separate power supply compatible with the fan.
STEP 6: ATTACH THE V
DD
AND V
S
POWER SUPPLIES
Before connecting the power supply, it is critical that you verify that the WLD will be within the Safe
Operating Area. (Reference page 5.)
The WLD3393 has two power supply connections, V
S
and V
DD
. V
S
provides power for driving the
laser (minimum current capacity greater than limit current setting). V
DD
provides power to the control
electronics (minimum 100 mA). V
DD
can range from +5 to +12 V. V
S
can range from +4.5 to +12 V.
For simple operation tie V
DD
to V
S
.
V
S
and V
DD
can be connected using the Power Select Jumper. See
Step 3 for location. Use PGND for the power return. The common (COM) terminal on the WLD3393
is not intended to act as a power connection, but as the low noise ground reference for connecting an
external VSET source, and for monitoring the IMON, PMON, and PDM signals.
A separate V
S
power supply allows the output current stage to operate below the minimum 5 V required
for the control electronics or up to the +12 V maximum (for multiple laser diodes in series). Select V
S
approximately 2.0 volts above the maximum voltage drop across the laser diode to reduce the power
dissipation in the WLD3343 component and minimize your heatsinking requirements. Note that for
type C laser diodes in Constant Power mode V
DD
must be greater than or equal to V
S
to keep the
photodiode signal in range.
The 2.5 mm input power jack attaches to V
DD
. You can use the Wavelength PWRPAK power supplies
with this jack. Use either the power jack or the power inputs on the connector harness, not both.
CONFIGURING THE EVALUATION BOARD
