SPNova InGaN - Optical And Electrical Characteristics Across Operational Temperature Range Introduction: Light emitting diode’s (LED) operational characteristics are very dependent on the operating temperature. As current flows through the LED, the junction temperature will increase until a steady state is reached. The final steady state temperature will depend on the ambient temperature and the thermal properties of the surrounding materials. Luminous intensity, dominant wavelength and forward voltage are the major parameters that will shift according to the junction temperature of the LED. This variation is mainly due to the natural behavior of III-IV compound semiconductor material used in the fabrication of the LED chip. This document intends to describe the characteristics of the shift associated to junction temperature shift. Device: NPT-USS Forward Voltage Shift 1.1000 Normalized Vf 1.0500 1.0000 0.9500 0.9000 0 10 20 30 40 50 60 70 80 90 Junct Temp (C) Forward Voltage Shift Vs Junction Temperature 12/07/11 -1- Ver B SPNova InGaN – Optical and Electrical Characteristics Across Operational Temperature Range Luminous Intensity Shift 1.1000 Normalized IV 1.0500 1.0000 0.9500 0.9000 0.8500 0.8000 0 10 20 30 40 50 60 70 80 90 80 90 Junct temp (C) Luminous Output Vs. Junction Temperature Dominant Wavelength Shift 1.1000 Normalized WD 1.0500 1.0000 0.9500 0.9000 0.8500 0.8000 0 10 20 30 40 50 60 70 Junct tem p (C) WD Shift Vs Junction Temperature 12/07/11 -2- Ver B SPNova InGaN – Optical and Electrical Characteristics Across Operational Temperature Range Device: NPC-USS Forward Voltage Shift 1.1000 Normalized Vf 1.0500 1.0000 0.9500 0.9000 0 10 20 30 40 50 60 70 80 90 80 90 Junct temp (C) Forward Voltage Shift Vs Junction Temperature Luminous Intensity Shift 1.1000 Normalized IV 1.0500 1.0000 0.9500 0.9000 0.8500 0.8000 0 10 20 30 40 50 60 70 Junct temp (C) Luminous Output Vs. Junction Temperature 12/07/11 -3- Ver B SPNova InGaN – Optical and Electrical Characteristics Across Operational Temperature Range Dominant Wavelength Shift 1.1000 Normalized WD 1.0500 1.0000 0.9500 0.9000 0.8500 0.8000 0 10 20 30 40 50 60 70 80 90 70 80 90 Junct tem p (C) WD Shift Vs Junction Temperature Device: NPB-USS Forward Voltage Shift 1.1000 Normalized Vf 1.0500 1.0000 0.9500 0.9000 0 10 20 30 40 50 60 Junct Temp (C) Forward Voltage Shift Vs Junction Temperature 12/07/11 -4- Ver B SPNova InGaN – Optical and Electrical Characteristics Across Operational Temperature Range Luminous Intensity Shift 1.1000 Normalized IV 1.0500 1.0000 0.9500 0.9000 0.8500 0.8000 0 10 20 30 40 50 60 70 80 90 70 80 90 Junct tem p (C) Luminous Output Vs. Junction Temperature Dominant Wavelength Shift 1.1000 Normalized WD 1.0500 1.0000 0.9500 0.9000 0.8500 0.8000 0 10 20 30 40 50 60 Junct temp (C) WD Shift Vs Junction Temperature Note: All data are normalized to read at 25°C 12/07/11 -5- Ver B