Application Note

Light Emitting Diode

Heat Dissipation Performance of theNichia NVSxx19C Series LEDs

Table of contents
1. Overview ............................................................................... 2
2. Difference in the Electrode Configurations ........................... 2
3. Evaluation of the Heat Dissipation Capabilities .................... 3
4. Summary................................................................................ 8

The Nichia part numbers NVSx119C and NVSx219C within this document are merely Nichia’spart numbers for those Nichia products and are not related nor bear resemblance to any othercompany’s product that might bear a trademark.

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Application Note
1. Overview

Nichia presumes that the NVSxx19C series LEDs will be used for applications that are operated athigh currents. When the LED is operated at a high current, it produces a large amount of heat; if
this causes the LED temperature (TJ) to increase, it may cause issues (e.g. reduction in the luminous
flux according to the LED temperature characteristics). Ensure that when designing the PCB andthe luminaire, there are no issues with the thermal designs for the chosen application.

3.5

3.5

3.5
This application note provides the results of the evaluationof the heat dissipation3.5capabilities of the
2.9 0.4
2.9
NVSxx19C series LEDs as a discrete part (i.e. a single LED is soldered to a PCB) with an emphasison the difference in the LED electrode configuration between the NVSx219C and NVSx119C LEDs.

2. Difference in the Electrode Configurations

22As mentioned in the Overview, there is a difference in the electrode configuration between theseCathode MarkCathode Markmodels: the NVSx219C LEDs have a die heat sink that is electrically isolated from both the anodeelectrode and cathode electrode and the NVSx119C LEDs do not have a die heat sink. This is the
only difference that exists between these models, the other parts/materials used are the same.
Refer to Figure 1 for the common appearance of the NVSxx19C series LEDs, and Figures 2 and 3for the electrode configurations of the NVSx119C and NVSx219C LEDs.

3.2
0.5

3.2

1.3

0.5

3.2

0.45

3.2
2.4

Light Emitting Diode

Nichia’s NVSxx19C series LEDs offer two different types of electrode designs: LEDs with one
cathode and one anode electrode (i.e. NVSx119C) and LEDs with an electrically isolated die heatsink in addition to these two electrodes (i.e. NVSx219C). The thermal resistances (RθJS) from theLED die to the TS measurement point are the same for both of those types. However, the differencein the design of the LED (i.e. electrodes/heat sink pad on the back of the LED package) and/or thesoldering pad pattern of the printed circuit board (PCB) may cause the thermal path to change
causing a difference in the heat dissipation.

CathodeAnodeダイヒートシンク
Die Heat
Heat Sink
Sink
DieFigure 1. Appearance of theNVSxx19C series LEDs

Figure 2. Electrode Configurationof the NVSx219C LEDs

CathodeAnodeFigure 3. Electrode Configurationof the NVSx119C LEDs

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Application Note
When the LED is operated, it produces heat at the LED die. This heat is conducted to the LED
ceramic substrate and then to the PCB (i.e. the copper layer) via the electrodes, spreading over thePCB. For the NVSx219C LEDs, heat is conducted to the PCB (i.e. the copper layer) via the cathodeelectrode, die heat sink, and anode electrode; for the NVSx119C LEDs, it is conducted via thecathode and anode electrodes.
Refer to Figure 4 for the NVSx219C LEDs’ thermal path from the LED die to the PCB and Figure
5 for the NVSx119C LEDs’ thermal path.
LED Chip
Ceramic Substrate

Flow of Heat

Copper Layer

Light Emitting DiodeTS Measurement
Point

Solder Mask

Copper LayerTS Measurement
Point

PCB

Figure 4. Thermal Path of the NVSx219C LEDs

LED Chip
Ceramic Substrate

Flow of Heat

Solder Mask

PCB

Figure 5. Thermal Path of the NVSx119C LEDs

3. Evaluation of the Heat Dissipation Capabilities
3.1 Evaluation Method/Conditions
To verify the effect of the difference in the electrode design on the heat dissipation capability, Nichia
has measured the junction temperatures and thermal resistances of the NVSxx19C Series LEDs (i.e.
NVSx119C and NVSx219C) using two different types of PCBs: FR-4 glass epoxy PCBs andaluminum core PCBs. These PCBs were designed to have copper layers with the same total area,
though different pattern designs.
For the NVSx219C LEDs, three different copper layer pattern designs were used to determine
whether this difference has an effect on the heat dissipation:
Copper Layer Pattern 1: The copper area that the die heat sink is soldered to is significantly larger
than the other two copper areas (i.e. copper area that the anode/cathodeelectrodes are soldered to).
Copper Layer Pattern 2: All the three copper areas that the anode/cathode electrodes and die heatsink are soldered to have approximately the same area.
Copper Layer Pattern 3: The copper areas that the anode/cathode electrodes are soldered to haveapproximately the same area. The die heat sink is designed to be soldered
to the same copper area with the cathode electrode.
For the NVSx119C LEDs, a copper layer pattern design was used:
Copper Layer Pattern 4: The copper areas that the anode/cathode electrodes are soldered to haveapproximately the same area.
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Application Note
Refer to Table 1 for the e Soldering Pad Patterns, Table 2 for the copper layer patterns of the FR-4
PCBs used, and Table 3 for the copper layer patterns of the aluminum core PCBs on Page 5.
Table 1. Soldering Pad Patterns
NVSx219C: Copper are that the cathodeelectrode is soldered to4.1

1.3

1.2

Soldering Pad

NVSx119C
0.6: Copper area that the die heatsink is soldered to: Copper area that the anodeelectrode is soldered to3.5

0.4

0.5

3.3

Part NumberPatterns0.5(単位 Unit: mm)
4.1

Light Emitting Diode

Table 2. FR-4 Glass Epoxy PCB Copper Layer Patterns: Through hole
NVSx219C

Item

Pattern 1

1

Pattern 22

NVSx119C
Pattern 3

3

Pattern 44

Top of the PCB
CopperLayer
Pattern
Back of the PCB

PCB Dimensions

50mm×50mm×t1.6

Copper Layer Thickness

70μm

Top of the PCB

Die Heat Sink

1247

406

Copper

Anode

67

488

655

691

Cathode

67

488

728

691

Area[mm ]Subtotal

1381

1382

1383

1381

Back of the PCB

Die Heat Sink

1464

406

Copper

Anode

529

732

732

Cathode529

732

732

Layer
2Layer2

Area[mm ]Subtotal

1464

1464

1464

1464

Total[mm ]

2845

2847

2847

2846

2

Notes:
1: The copper area that the die heat sink is soldered to is significantly larger than the other two copper areas (i.e.
copper area that the anode/cathode electrodes are soldered to).
2: All the three copper areas that the anode/cathode electrodes and die heat sink are soldered to have approximately
the same area.
3: The copper areas that the anode/cathode electrodes are soldered to have approximately the same area. The heat sinkis designed to be soldered to the same copper area with the cathode electrode.
4: The copper areas that the anode/cathode electrodes are soldered to have approximately the same area.

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Application Note
: Copper are that the cathodeelectrode is soldered to: Copper area that the die heatsink is soldered to: Copper area that the anodeelectrode is soldered toTable 3. Aluminum Core PCB Copper Layer Patterns
NVSx219C

Item

Pattern 1

1

Pattern 22

NVSx119C
Pattern 33Pattern 44

CopperLayer

Top of the PCB

Light Emitting Diode

Pattern
PCB Dimensions

50mm×50mm×t1.7

Copper Layer Thickness

70μm

Insulating Layer’s Thermal

4.5W/m・K

Conductivity
Die Heat Sink

1312

412

Anode67

518

688

723

Cathode

67

518

761

723

Total[mm ]

1446

1448

1448

1447

CopperLayer
2Area[mm ]2

Notes:
1: The copper area that the die heat sink is soldered to is significantly larger than the other two copper areas (i.e.
copper area that the anode/cathode electrodes are soldered to).
2: All the three copper areas that the anode/cathode electrodes and die heat sink are soldered to have approximately
the same area.
3: The copper areas that the anode/cathode electrodes are soldered to have approximately the same area. The heat sinkis designed to be soldered to the same copper area with the cathode electrode.
4: The copper areas that the anode/cathode electrodes are soldered to have approximately the same area.

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Application Note
3.2 Evaluation Results
3.2.1 Heat Dissipation Capabilities of the LEDs when soldered to the FR-4 Glass Epoxy PCBs
The evaluation verified that when the NVSx119C LEDs and NVSx219C LEDs were soldered tothe FR-4 glass epoxy PCBs, the NVSx119C LEDs achieved the lowest values in both thermal
resistance and junction temperature (i.e. Copper Layer Pattern 4); this leads to the conclusion thatthe NVSx119C LEDs could have better heat dissipation than NVSx219C LEDs.
For the evaluation results of the NVSx219 LEDs alone, the LEDs had better heat dissipation whenused with Copper Layer Patterns 2 and 3 than Copper Layer Pattern 1.
Refer to Table 4, Figures 6 and 7 below for more details on the evaluation results.

Light Emitting DiodeTable 4. Evaluation Results for the Heat Dissipation Capabilities

IF=1800mA, TA=25℃

NVSx219C

Conditions

Pattern 1

1

Pattern 22

NVSx119C
Pattern 3

3

Pattern 44

Thermal Resistance (RθJA) [℃/W]

33.8

25.4

25.3

23.9

Junction Temperature (TJ) [℃]

206.6

160.3

159.4

153.1

*The absolute maximum junction temperature of the NVSxx19C series LEDs (i.e. NVSx119Cand NVSx219C) is 150°C. Ensure that when using the LEDs, the absolute maximum junction
temperature is not exceeded. The data above should be used for reference purpose only.
FR-4 Glass Epoxy PCB (RθJA)
Measurement Conditions: TA=25℃, Sample Size=3 LEDs x 1 lot
40

220

NVSx219C

35

NVSx119C

NVSx219C

200

NVSx119C

180

30160

TJ[℃]

RθJA [℃/W]

FR-4 Glass Epoxy PCB (TJ)
Measurement Conditions: TA=25℃, Sample Size=3 LEDs x 1 lot

25140

20120

15100

1080

Pattern 11

Pattern 22

Pattern 11

Pattern 22

Pattern 33

Pattern 33

Pattern 44

Pattern 44

Figure 6. Evaluation Results for the Thermal
Resistance (RθJA)

Pattern 11

Pattern 11

Pattern 22

Pattern 22

Pattern 33

Pattern 33

Pattern 44

Pattern 44

Figure 7. Evaluation Results for the Junction
Temperature (TJ)

Notes:
1: The copper area that the die heat sink is soldered to is significantly larger than the other two copper areas (i.e.
copper area that the anode/cathode electrodes are soldered to).
2: All the three copper areas that the anode/cathode electrodes and die heat sink are soldered to have approximately
the same area.
3: The copper areas that the anode/cathode electrodes are soldered to have approximately the same area. The heat sinkis designed to be soldered to the same copper area with the cathode electrode.
4: The copper areas that the anode/cathode electrodes are soldered to have approximately the same area.
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Application Note
3.2.2 Heat Dissipation Capabilities of the LEDs when soldered to the Aluminum Core PCBs
The evaluation with the aluminum core PCBs verified that the NVSx119C LEDs and NVSx219CLEDs have very similar heat dissipation.
Refer to Table 5 and Figures 8 and 9 below for more details on the evaluation results.
Table 5. Evaluation Results for the Heat Dissipation Capabilities
NVSx219CConditions

Pattern 11

Pattern 2

NVSx119C
Pattern 3

3

Pattern 44

14.1

14.4

13.9

13.8

Junction Temperature (TJ) [℃]

102.2

103.2

101.3

101.2

40

Aluminum Core PCB (TJ)
Measurement Conditions: TA=25℃, Sample Size=3 LEDs x 1 lot
220

NVSx219C

35

NVSx119C

NVSx119C

NVSx219C

200
18030160

TJ[℃]

RθJA [℃/W]2Thermal Resistance (RθJA) [℃/W]

Aluminum Core PCB (RθJA)
Measurement Conditions: TA=25℃, Sample Size=3 LEDs x 1 lot

Light Emitting Diode

IF=1800mA, TA=25℃

25140

20120

15100

1080

Pattern 11

Pattern 22

Pattern 11

Pattern 22

Pattern 33

Pattern 33

Pattern 44

Pattern 44

Figure 8. Evaluation Results for the ThermalResistance (RθJA)

Pattern 11

Pattern 11

Pattern 22

Pattern 22

Pattern 33

Pattern 33

Pattern 44

Pattern 44

Figure 9. Evaluation Results for the Junction
Temperature (TJ)

Notes:
1: The copper area that the die heat sink is soldered to is significantly larger than the other two copper areas (i.e.
copper area that the anode/cathode electrodes are soldered to).
2: All the three copper areas that the anode/cathode electrodes and die heat sink are soldered to have approximately
the same area.
3: The copper areas that the anode/cathode electrodes are soldered to have approximately the same area. The heat sinkis designed to be soldered to the same copper area with the cathode electrode.
4: The copper areas that the anode/cathode electrodes are soldered to have approximately the same area.

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Application Note
4. Summary

Light Emitting Diode

Based on the evaluation results above, Nichia has concluded that:
1. When the NVSx119C/NVSx219C LEDs are soldered to an FR-4 glass epoxy PCB and operated,
the NVSx119C LEDs achieve better dissipation than the NVSx219C.
2. When these LEDs are soldered to an aluminum core PCB and operated, no significant
difference is observed in the heat dissipation.
The NVSx119C LEDs have electrodes larger than the total area of the electrodes/die heat sink of
the NVSx219C LEDs. These electrodes will be an advantage in dissipating the heat from the LED
to the PCB. However, if sufficient heat dissipation has been achieved (e.g. using an aluminum core
PCB with the LEDs), the difference will be less apparent. Additionally, these evaluations wereperformed by using test PCBs with one LED per board; the data may change depending on the PCB
layout and/or operating conditions. Use the data/information provided in this application note forreference purposes only.

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Application Note

Light Emitting DiodeDisclaimer
This application note is a controlled document of Nichia Corporation (Nichia) published to provide
technical information/data for reference purposes only. By using this application note, the user agrees
to the following: This application note has been prepared solely for reference on the subject matters incorporated
within it and Nichia makes no guarantee that customers will see the same results for their chosenapplication.
 The information/data contained herein are only typical examples of performances and/orapplications for the product. Nichia does not provide any guarantees or grant any license underor immunity from any intellectual property rights or other rights held by Nichia or third parties.
 Nichia makes no representation or warranty, express or implied, as to the accuracy, completenessor usefulness of any information contained herein. In addition, Nichia shall not be liable for any
damages or losses arising out of exploiting, using, or downloading or otherwise this document, or
any other acts associated with this document.
 The content of this application note may be changed without any prior or subsequent notice.
 Copyrights and all other rights regarding the content of this document are reserved by Nichia or
the right holders who have permitted Nichia to use the content. Without prior written consent of
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form or by any means, whether in whole or in part, including modifications or derivative works
hereof, is strictly prohibited.

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NICHIA CORPORATION
http://www.nichia.co.jp

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