LDTC Series 500 mA Laser Driver & Thermal Control

  • Low noise LD current up to 500 mA
  • Slow-Start & Brownout Protection
  • Constant Current or Constant Power
  • Adjustable Laser Diode Current Limit
  • Remote TTL Shutdown or Interlock
  • Small package 2.35" x 2.9" x 1.075"
  • Failsafe Setpoint default for D/A
  • Drive ±2.2 A of TEC or RH Current
  • Single Power Supply Operation
  • Chassis mount includes all cables

From: $434.00

Bulk Pricing (2 - 9): $391.00

Contact Factory for OEM Pricing
Price adjustments will be reflected in the cart. For availability information please contact us. All prices are in US dollars and are subject to change without notice. Prices do not include shipping charges. An additional OEM discount applies on orders over 9 pieces. Contact factory for pricing. If ordering from or shipping to Australia, China, Hong Kong or Israel please contact your distributor.

The LDTC Laser Diode Driver and Temperature Controller combines Wavelength’s proprietary FL500 and highly stable WTC3243 in one compact module. LDTC modules are in use around the world providing trouble-free reliability in range finders, telecom laser modules, military-aerospace research and development, airborne metrology, academic research, laser diode LIV testers, and more.


The LDTC module requires minimal overhead electronics, so your engineers can focus on high-level design features that differentiate you from your competitor. The compact LDTC is easily mounted in your laser system, with latching connectors for easy manufacturing. The flexibility of the LDTC design allows the controller to be operated from a single power supply. The power supplies can also be separated, if your application requires higher compliance voltage.


The laser driver is based on our popular FL500, known for low noise output and trouble-free operation. Two models are available, providing either 500 mA (LDTC0520) or 1.0 A output current (LDTC1020). The current limit circuit cleanly clamps laser diode current without ringing or overshoot, and recovers without inducing a phase shift in a modulated laser signal.

The temperature controller is designed around the WTC3243, our ultra-stable temperature control module known for the ability to sweep load temperature across ambient. Independent cooling- and heating-current limits allow the LDTC to be used with thermoelectric coolers or resistive heaters and either negative or positive temperature coefficient sensors.

Remote computer control is available using the USBKIT, which also allows graphing and datalogging.

Wavelength has done critical research and design work into safely controlling laser diodes. The result is a module that saves you money in development and manufacturing, and delivers trouble-free service over the life of the system.


Download the brochure to view a more detailed specification chart, and then call Wavelength’s sales engineers so we can help you choose the right driver for your application.

Free, effective, and responsive technical support is available to simplify integration of Wavelength products into your OEM design. Standard product can be easily modified to meet your application requirements.

Low noise: 3 µA RMS noise at full scale
24 Hour Current Stability at ambient 25°C: 50-75 ppm

Supply Range: +3 to +12 V
Laser Diode Output Current: up to 500 mA

Delay: 100 msec. After the delay, current will rise to the level dictated by the setpoint voltage. This delay ensures that all control electronics are functioning before current flows to the laser diode. The delay time is set with internal components.
Slow Start: 15 mA / msec
Rise / Fall times: 300 nsec (to full scale)

TTL Compatible RESET / ENABLE input is active LO.

Bandwidth: 500 kHz – Constant Current sine wave
Bandwidth: 100 kHz – Constant Current square wave

Brownout protection is provided if VDD drops below 2.7 V. In this case, the RESET circuit is triggered immediately (within 100 μsec) to reduce the current through the laser diode.

Maximum Power Dissipation (configured as single 500 mA drive): 2 W

Supply Range: +4.5 to +30 V
Temperature Control Output Current: up to ±2.2 A
Temperature Stability: 0.002°C (10 kΩ thermistor at 25°C) over one hour
Stability across ambient: 0.005°C (10 kΩ thermistor at 25°C) over an hour — Ideal for scanning applications

Setpoint vs. Actual Temperature Accuracy: less than 2 mV typical

-Heat and Cool Current Limits
-Default Setpoint: If external setpoint drops below 0.3 V, an onboard default circuit sets it to 1 V. [25°C with a 10 kΩ thermistor]
-PI controller
-Compatible with multiple sensors
-Adjustable sensor bias current optimizes sensor feedback voltage
-Can operate with unipolar current for Resistive Heaters

Maximum Power Dissipation: 9 W
Heatspreader Temperature Rise: 30°C / W without external heatsinking

Chassis Mount Module size: 60 x 74 x 28 mm

Top View of LDTC1020 or LDTC0520

Top View of LDTC1020 or LDTC0520

Related FAQs

FAQ1001: What does the Compliance Voltage specification in laser diode drivers mean?
FAQ1007: What limits the temperature control range of a temperature controller?
FAQ1009: Why won't my temperature controller settle my load to temperature?
FAQ1010: Why does it take so long to settle to the setpoint temperature?
FAQ1011: Why won't my load stabilize to your temperature controller specification?
FAQ1012: Why is my load heating when it should be cooling?
FAQ1014: What DC power supplies do you recommend to achieve the stability specifications listed in your manuals?
FAQ1015: Should I use a switching power supply for my application?
FAQ1016: How do I view and print your manuals on-line?
FAQ1017: An empty screen appears when I try opening a PDF manual. What does this mean?
FAQ1019: Which address do I use to remit payment or a purchase order?
FAQ1022: Where do I send my unit for repair or calibration?
FAQ1085: Do the temperature controllers always provide full current to the driven element (a TEC or Peltier device, or resistive heater) when the actual temperature does not equal the set point temperature?
FAQ1117: The temperature of my resistive heater is slow to stabilize and is not within specification.
FAQ1118: How do I determine whether to operate in Constant Current (CC) or Constant Power (CP) mode?
FAQ1120: What does the Compliance Voltage specification in temperature controllers mean?
FAQ1150: What are the differences between a wavelength meter and a spectrometer?
FAQ1158: What software can I use for mechanical downloads?
FAQ1161: What are some important parameters to consider before purchasing a product?
FAQ1163: How does grounding the thermoelectric cooler cable on temperature controllers affect the noise level?
FAQ1164: Which Wavelength products are best for superluminescent diodes?
FAQ1165: What are some important features of vertical-cavity surface-emitting lasers, and what Wavelength products can be used to drive them?
FAQ1166: What characteristics do Interband Cascade Lasers have, and what are appropriate Wavelength Electronics drivers for them?


THERM-PSTThermal Paste$19
MULTI-HTSKMULTI-HTSK Multi-Product Heat Sink$57
HTSK-BRKTHeatsink Bracket for MULTI-HTSK and MULTI-HTSK-HI$28
TCS10K5TCS10K5 10 kΩ Thermistor (0.5x3mm) Sold in 5-packs$97
TCS605TCS605 5 kΩ Thermistor (2x3mm) Sold in 10-packs$97
TCS610TCS610 10 kΩ Thermistor (2x3mm) Sold in 10-packs$97
TCS620TCS620 20 kΩ Thermistor (2x3mm) Sold in 10-packs$97
TCS650TCS650 50 kΩ Thermistor (2x3mm) Sold in 10-packs$97
TCS651TCS651 100 kΩ Thermistor (2x3mm) Sold in 10-packs$97
LDMOUNT-5ALDMOUNT 5A Butterfly Laser Diode Mount$340
USBKITUSB Interface for Laser Diode and Temperature Controllers$350USB Interface for Laser Diode and Temperature Controllers

Related Parts

FL500FL500 500 mA Laser Diode Driver$56FL500 Laser Diode Driver
LDTC1020LDTC Series 1 A Laser Driver & Thermal Control$489ldtc1020
WTC3243WTC3243 2.2 A Temperature Controller$97wtc3243