ILX Lightwave LDT5948 – Precision Temperature Controller

The ILX Lightwave LDT5948 is a precision temperature controller for laser diode and optoelectronic component testing. It delivers ±0.005°C setpoint accuracy with 0.001°C resolution over a -50°C to +250°C range, maintaining long-term stability of 0.005°C at both 1-hour and 24-hour intervals. The fully programmable digital PID control loop features auto-tune capability for independent system optimization.

The controller manages thermoelectric (TE) modules through independent heating and cooling limits, with output current from -5.00 to +5.00 A and voltage from -12 to +12 V at 60 W maximum power. TEC noise remains below 15 mA typical, while current setpoint accuracy reaches ±0.03 A (0.001 A resolution) and voltage setpoint accuracy ±0.05 V (0.001 V resolution). Flexible sensor support accommodates thermistors, IC sensors, and platinum RTDs via four-wire measurement topology for high-accuracy voltage and resistance readings.

AC resistance measurement characterizes TE module performance across two ranges: 10 µA excitation (10 to 600 kΩ) and 100 µA excitation (1 to 60 kΩ).

Technical Specifications

• Range: -50°C to +250°C


• Setpoint accuracy: ±0.005°C (typical)


• Setpoint resolution: 0.001°C


• Long-term stability (1 hr / 24 hr): 0.005°C


• Programmable digital PID loop with auto-tune


• Independent heating and cooling limits Thermoelectric Output


• Current: -5.00 to +5.00 A


• Voltage: -12 to +12 V


• Power: 60 W maximum


• Current accuracy: ±0.03 A (0.001 A resolution)


• Voltage accuracy: ±0.05 V (0.001 V resolution)


• TEC ripple/noise: <15 mA typical Measurement & Sensing


• Sensor types: Thermistor, IC, Platinum RTD


• Four-wire sensor measurements


• Four-wire voltage measurement


• AC resistance measurement (TE characterization)


• Resistance ranges: 10 to 600 kΩ @ 10 µA; 1 to 60 kΩ @ 100 µA

Key Features

• Auto-tune PID eliminates manual control loop tuning


• Four-wire architecture eliminates lead resistance error


• Multi-sensor compatibility supports diverse system designs


• Dual-polarity output drives heating and cooling


• AC resistance mode characterizes thermoelectric module performance

Typical Applications

• Internal TE control for laser diode stabilization


• Precision temperature management in optoelectronic test systems


• Thermoelectric module characterization and optimization

Compatibility & Integration

• GPIB and RS-232 remote interfaces


• Front-panel mode selection: ITE, VTE, Snsr, Rac


• Programmable trigger I/O for automated test sequences


• Operating range (IC sensors): -50°C to +150°C


• Operating range (RTD sensors): -50°C to +199.999°C