ILX Lightwave LDX-32420: Precision Current Source, 10/20A, LDX-36000 Series

The ILX Lightwave LDX-32420 is a precision current source engineered to drive high-power laser diodes and similar devices requiring stable, accurate current control. Part of the LDX-36000 Series, this instrument delivers up to 20 A of DC current across dual selectable ranges (10 A and 20 A) with 4 V compliance voltage. It operates in constant current and constant optical power modes, incorporating real-time forward voltage measurement via four-wire sensing and integrated photodiode current measurement with adjustable reverse bias.

The unit combines low-noise operation with modulation capability to 100 kHz bandwidth, making it suitable for both CW and dynamic laser characterization. Comprehensive protection circuitry - including adjustable voltage and current limits, output shorting relays, and transient suppression - safeguards connected devices during power-up and normal operation. IEEE488/GPIB and USB 2.0 interfaces enable remote control and integration with automated test systems; LabVIEW drivers are available.

Note: This model has been discontinued by the manufacturer.

Technical Specifications

• Maximum output: 20 A across dual ranges (10 A, 20 A)


• Setpoint resolution: 1 mA


• Setpoint accuracy: 0.1% or ±0.1% reading + 10 mA


• Output stability (1 hour): ±50 ppm


• Noise/ripple (rms): <5 mA or <100 ppm at full scale


• Modulation bandwidth: DC to 100 kHz Forward Voltage Measurement


• Accuracy: ±5 mV


• Resolution: 1 mV


• Four-wire sensing system Photodiode Current Measurement


• Range: 0 to 5000 µA


• Accuracy: ±2 µA


• Adjustable reverse bias: 0 to -5 V Voltage Compliance: 4 V

Key Features

• Constant current (CW) operation in low and high bandwidth modes


• Constant optical power mode with programmable photodiode responsivity


• Output shorting relays and slow turn-on/off circuits


• Fast error detection and intermittent contact protection


• 5-digit green LED display


• Power input: 220 VAC

Typical Applications

• High-power single-emitter laser diode testing and characterization


• Precision current control for high-current optical devices


• Modulated and CW laser operation with optical feedback control

Compatibility & Integration

• IEEE488/GPIB interface


• USB 2.0 connectivity


• LabVIEW driver support