© 2022
9
WLD SERIES LASER DIODE DRIVERS
OPERATING INSTRUCTIONS
— GENERAL
The WLD33ND drivers have dual in-line pin (DIP)
packaging, and are intended to be mounted onto a circuit
board. Parameters including output current range, output
current limit, photodiode current range, and operating mode
are configured by proper choice of external components.
We recommend using a test load until you are familiar with
operation of the driver. Refer to
for test load
information.
These instructions are broken into three sections. The first
covers generally applicable operating instructions that are
relevant whether or not the optional evaluation board is
being used. The second configures the driver for standalone
operation without the evaluation board (
third configures the driver for operation with the evaluation
board (
).
NECESSARY EQUIPMENT
The following equipment is the minimum necessary to
configure the WLD33ND for basic operation:
• WLD33ND controller
• Digital voltmeter, 4-½ digit resolution recommended
•
Test load for configuring the driver
• Laser diode, mount, and optional temperature control
system
• Recommended heat sink and optional fan
»
WTW002 Thermal Washer
»
WHS302 Heatsink
»
WXC303 (+5 VDC) or WXC304 (+12 VDC) Fan
• Custom circuit board, or WLD33ND-EV evaluation
board
• Power supply (see below)
POWER SUPPLY REQUIREMENTS
Linear-regulated or low-noise switching power supplies can
be used. We recommend using power supplies with noise
specifications suitable for your application.
For WLD33ND, WLD33ND-3A, WLD33ND-2L,
WLD33ND-3L:
• 4.5 to 12.5 VDC power supply rated for 1.1-times the
maximum laser diode current, plus 150 – 250 mA for
the electronics.
For WLD33ND-HB:
• 3.3 to 6 VDC power supply rated for 1.1-times the
maximum laser diode current, plus 150 – 250 mA for
the electronics.
•
The HB offers low voltage operation for use with a
Lithium-ion battery or other low voltage power supplies.
PREVENT DAMAGE FROM ELECTROSTATIC
DISCHARGE
Before proceeding, it is critical that you take precautions to
prevent electrostatic discharge (ESD) damage to the driver
and your laser. ESD damage can result from improper
handling of sensitive electronics, and is easily preventable
with simple precautions.
For more information on ESD, see Application Note
AN-LDTC06: Basics: Electrostatic Discharge (ESD)
.
We recommend that you always observe ESD precautions
when handling the WLD33ND driver and your laser diode.
ONLINE TOOLS AVAILABLE
An online tool, the
, is available to
assist in the choosing of external components that impact
operation. It is customizable for laser type, and operation
mode. This automatically calculates the required external
component values including R
LIM
, R
SENSE
, V
SET
, and R
PD
(if
operating in Constant Power mode).
OPERATION MODE
The WLD Series supports Constant Current and Constant
Power modes of operation (with the exception of the -2L
and -3L models, which only support Constant Current).
Depending on the chosen operation mode, either the
current through the laser diode or the current through the
photodiode will be maintained at a fixed level.
!
Do not switch the control mode while the
output is enabled and driving a laser diode.
The laser diode may be damaged or
destroyed.
Constant current through the laser diode is referred to as
Constant Current mode, and is abbreviated CC. In CC
mode, the setpoint is directly proportional to the laser diode
current.
Constant current through the monitor photodiode is referred
to as Constant Power mode and is abbreviated CP. In CP
mode, the setpoint is directly proportional to the photodiode
current, allowing for control of the power emitted from the
laser diode.
