Wavelength Electronics WHS302, Datasheet And Operating Manual

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WLD SERIES LASER DIODE DRIVERS
PIN DESCRIPTIONS
Table 1. Pin Descriptions
PIN LABEL NAME PIN DESCRIPTION
1 SHD
Shutdown
Laser Diode
Output Current
Enable or disable output current to the laser diode using this pin.
To ENABLE: Float or connect a zero volt signal to this pin.
To DISABLE: Connect a +3 V or greater signal to this pin.
2 V
SET
Setpoint
Voltage Input
or Modulation
Input
Connect a voltage source between this pin and Pin 7 (GND) to control either the laser diode
current in Constant Current mode or the laser diode power in Constant Power mode.
Range is 0-2 V full scale.
Input impedance is 20 kΩ.
Offset voltage is 0.5 V when open (applies to Revision D forward).
Do not let this pin float, or damage to the load may result.
3 IMON
Laser Diode
Current
Monitor
Monitor the laser diode forward current using this pin. The laser diode current monitor
produces a voltage proportional to the current flowing through the laser diode.
Standalone:
Transfer function depends on R
SENSE
value. See Equation (11) on page 15 .
Evaluation Board: See
Table 10
on
page 20
for the transfer function.
4 PMON
Photodiode
Current
Monitor
Monitor the laser diode power using this pin. The photodiode current monitor produces a
voltage proportional to the current produced by the laser diode monitor photodiode.
Standalone: Transfer function depends on R
PD
value. See Equations (12) & (13) on page 15 .
Evaluation Board:
See Table 11 on page 20 for the transfer function.
5 MODE
Mode
Configuration
Configure either Constant Current or Constant Power operation using this pin.
Constant Current:
Install a 1 kΩ resistor between this pin and Pin 6 (LIM).
Constant Power:
Install a 1 μF capacitor between this pin and Pin 6 (LIM).
6 LIM
Laser Diode
Current Limit
A resistor connected between this pin and Pin 7 (GND) limits the maximum amount of forward
current through the laser diode. See page 11 for more information.
7 GND
Power Supply
Ground
Connect the V
DD
power supply ground connection to this pin.
8 RS+
Laser Diode
Current Sense
Resistor
Positive Input
Connect this pin directly to the positive side of the laser diode current sense resistor. The
resistance value of R
SENSE
determines the range of forward current through the laser diode.
9 OUTB Output B Connect this pin to the positive side of R
SENSE
.
10 RS-
Laser Diode
Current Sense
Resistor
Negative Input
Connect this pin directly to the negative side of the laser diode current sense resistor. The
resistance value of R
SENSE
determines the range of forward current through the laser diode.
11 OUTA Output A
How this pin is configured depends on laser type.
Type A/B:
Connect this pin to the cathode connection of the laser diode.
Type C:
Connect this pin to Pin 14 (V
DD
).
12 PD+
Photodiode
Current Sense
Resistor
Positive Input
How this pin is configured depends on both laser type and operation mode.
Constant Current:
For all laser types, connect both this pin and Pin 13 (PD-) to Pin 7 (GND).
Constant Power:
For Type A/B lasers, connect this pin to the anode of the photodiode. For
Type C lasers, connect this pin to Pin 14 (V
DD
)
13 PD-
Photodiode
Current Sense
Resistor
Negative Input
How this pin is configured depends on both laser type and operation mode.
Constant Current: For all laser types, connect both this pin and Pin 12 (PD+) to Pin 7 (GND).
Constant Power: For Type A/B lasers, connect this pin to Pin 7 (GND). For Type C lasers,
connect this pin to the cathode of the photodiode.
14 V
DD
Power Supply
Input
Power supply input for the internal control electronics.
Supply range input for this pin is model-dependent.