Failure Modes and Countermeasures in Actual Use of NTC Thermistors
Its main applications include temperature sensing in electronic equipment and temperature compensation for module products.
However, if the user misuses the product, it may not function properly and, in the worst case, this may cause malfunctions.
This page introduces the causes and countermeasures for ”cracks” and ”melting of ceramics” as failure modes caused by improper use of NTC thermistors.
Table of Contents
- Outline
- Failure Mode (1) ＜Cracks＞
1st Cause: Excessive solder
Countermeasures
2nd Cause: Post-mounting Stress
Countermeasures - Failure Mode (2) ＜Melting of ceramics＞
1st Cause: Overcurrent
Countermeasures - Summary
- Product List
Outline
Failure Mode (1) ＜Cracks＞
The most common failure mode is 'cracking'.
Cracks are sometimes caused by mechanical stress during or after mounting on the board. Two common causes are "Excessive solder" and "post-mounting stress".
1st Cause: Excessive solder
When mounting NTC thermistors on boards, Excessive solder may cause cracking.
As the solder quantity increases, the stress on the NTC thermistor increases.
This is due to bending stress caused by the solder, which may lead to cracking when the applied solder is too much.
However, if there is too little solder, there is a risk of poor connection or chip or the joint may be unstable and chip dropout.
Thereefore, it is important to apply an appropriate quantity of solder.
Countermeasures
When designing the land pattern on the board, set the pattern shape and dimensions to ensure appropriate application of the solder.
Please use the data sheets and brochures(catalogs) available on our website to check the recommended land pattern dimensions for your product.
By designing the land pattern according to the recommended dimensions, you can avoid excessive or insufficient solder quantity.
For example, for our 1.6 x 0.8 mm NTC thermistor, the following land pattern dimensions are recommended:
2nd Cause: Post-mounting stress
If an NTC thermistor is solder-mounted on a mounting board that has been deformed due to a split plate or screw, cracks may occur due to stress.
In particular, it is important to note that the NTC thermistor is more prone to high amount of stress around the split plate.
Countermeasures
This stress due to bending of the board varies greatly depending on the placement of components on the board where the NTC thermistor is mounted.
As an example, stress can be reduced by placing the chip parallel to the split-plate surface rather than perpendicular to it. Also, the further away it is from the split plate section, the more stress is reduced.
The risk of cracking can be greatly reduced by designing the board so that the NTC thermistor is positioned against bending stress.
In addition, even without split plates, cracking may still occur due to deflection stress caused by bending of the board, dropping, or impact.
After mounting the NTC thermistor, please be careful not to apply external stress to the board.
Failure Mode (2) ＜Melting of ceramics＞
Since NTC thermistors are temperature-sensing devices, self-heating should be reduced as much as possible in order to accurately detect temperature.
However, there are cases where the thermistor’s temperature exceeds its melting point, which could melt the board if excessive electrical load continues to be applied.
1st Cause: Overcurrent
As mentioned earlier, one of the causes of ceramics melting is the application of large electrical load to the NTC thermistor.
Since NTC thermistors have negative electrical resistance in relation to temperature, their resistance decreases due to self-heating that occurs when excessive current flows through them.
Due to these electrical characteristics, continuous overcurrents that greatly exceed the allowable operating current can lead to "over heat," in which a decrease in resistance due to self-heating alternates with an increase in current due to the decrease in resistance. Then, if the internal temperature of the element exceeds the melting point of the ceramics, the element will melt.
Countermeasures
Make sure the components and design circuits do not apply current exceeding the permissive operating current.
For example, for our 1.0 x 0.5 mm NTC thermistors, the permissive operating current is specified as 0.03 to 0.21 mA.
(Note: In actual use, this varies depending on the land pattern, solder quantity, board material, etc.)
The permissive operating current is specified for each part number, and should be in accordance with the specified value of each NTC thermistor manufacturer.
As a countermeasure against overcurrent, a voltage divider circuit using a fixed resistor is effective.
Examples of circuits for each application are shown in the following pages for your reference.
We also have an online tool where you can select the optimum product and sensing circuit using our NTC thermistors.
You can use this tool to find the best solution to your product.
Summary
This page summarizes the NTC thermistor's failure modes, mainly due to misuse, and their countermeasures.
NTC thermistor failures due to improper use are not limited to those introduced here.
Detailed handling precautions are described in our product catalogs and delivery specifications.
We hope that you will find this information useful for the safe use and application of NTC thermistors.
Product List
Commercial Grade
| Produktbild | Serien, Typen | Größe LxW | Bauhöhe | Nominaler Widerstand [bei 25°C) | B-Wert [25/50℃] |
B-Wert [25/85℃] |
B-Wert [25/100℃] |
Produkt-Katalog | RoHS-Zertifikat | REACH-Zertifikat | Bestell-nummern-Übersicht |
|---|---|---|---|---|---|---|---|---|---|---|---|
 |
NTCG04
NTCG06 NTCG10 NTCG16 NTCG20 |
0.4x0.2mm
[EIA 01005] 0.6x0.3mm [EIA 0201] 1.0x0.5mm [EIA 0402] 1.6x0.8mm [EIA 0603] 2.0x1.2mm [EIA 0805] |
0.2mm
0.3mm 0.5mm 0.8mm 1.0mm |
10kΩ~470kΩ
40Ω~100kΩ 22Ω~470kΩ 30Ω~1MΩ 470Ω~150kΩ |
3380~4250K
3244~4485K 3244~4661K 3244~4661K 3060~4085K |
3413~4293K
3250~4550K 3250~4750K 3250~4750K 3150~4150K |
3445~4306K
3253~4327K 3251~4780K 3251~4780K 3670~4172K |
862KB
|
39KB
|
103KB
|
 |
|
B57*V2
|
1.0×0.5mm
[EIA 0402] 1.6×0.8mm [EIA 0603] 2.0×1.25mm [EIA 0805] |
0.6mm max.
0.9mm max. 1.3mm max. |
4.7kΩ～100kΩ
1.0kΩ～470kΩ 1.0Ω～470kΩ |
3940～4250K
3940～4386K 3940～4386K |
3980～4311K
3980～4455K 3980～4455K |
4000K±3%～4334K±1%
4000K±3%～4480K±3% 4000K±3%～4480K±3% |
421KB
|
209KB
|
209KB
|
|
|
|
B57621C5
|
3.2×1.6mm
[EIA 1206] |
1.3mm max.
|
1.0kΩ～10kΩ
|
3420~3470K
|
3440~3510K
|
3450K±3%～3530K±3%
|
532KB
|
|
| Produktbild | Serien, Typen | Größe LxW | Bauhöhe | Nominaler Widerstand [bei 25°C) | B-Wert [25/50℃] |
B-Wert [25/85℃] |
B-Wert [25/100℃] |
Produkt-Katalog | RoHS-Zertifikat | REACH-Zertifikat | Bestell-nummern-Übersicht |
|---|---|---|---|---|---|---|---|---|---|---|---|
|
|
NTCG04
NTCG06 NTCG10 NTCG16 NTCG20 |
0.4x0.2mm
[EIA 01005] 0.6x0.3mm [EIA 0201] 1.0x0.5mm [EIA 0402] 1.6x0.8mm [EIA 0603] 2.0x1.2mm [EIA 0805] |
0.2mm
0.3mm 0.5mm 0.8mm 1.0mm |
10kΩ~470kΩ
40Ω~100kΩ 22Ω~470kΩ 30Ω~1MΩ 470Ω~150kΩ |
3380~4250K
3244~4485K 3244~4661K 3244~4661K 3060~4085K |
3413~4293K
3250~4550K 3250~4750K 3250~4750K 3150~4150K |
3445~4306K
3253~4327K 3251~4780K 3251~4780K 3670~4172K |
862KB
|
39KB
|
103KB
|
|
|
|
B57*V2
|
1.0×0.5mm
[EIA 0402] 1.6×0.8mm [EIA 0603] 2.0×1.25mm [EIA 0805] |
0.6mm max.
0.9mm max. 1.3mm max. |
4.7kΩ～100kΩ
1.0kΩ～470kΩ 1.0Ω～470kΩ |
3940～4250K
3940～4386K 3940～4386K |
3980～4311K
3980～4455K 3980～4455K |
4000K±3%～4334K±1%
4000K±3%～4480K±3% 4000K±3%～4480K±3% |
421KB
|
209KB
|
209KB
|
|
|
|
B57621C5
|
3.2×1.6mm
[EIA 1206] |
1.3mm max.
|
1.0kΩ～10kΩ
|
3420~3470K
|
3440~3510K
|
3450K±3%～3530K±3%
|
532KB
|
209KB
|
209KB
|
|
Automotive Grade
| Produktbild | Serien, Typen | Größe LxW | Bauhöhe | Nominaler Widerstand [bei 25°C) | B-Wert [25/50℃] |
B-Wert [25/85℃] |
B-Wert [25/100℃] |
Produkt-Katalog | RoHS-Zertifikat | REACH-Zertifikat | Bestell-nummern-Übersicht |
|---|---|---|---|---|---|---|---|---|---|---|---|
|
|
NTCGS06
NTCGS10 NTCGS16 |
0.6×0.3mm
[EIA 0201] 1.0×0.5mm [EIA 0402] 1.6×0.8mm [EIA 0603] |
0.3mm
0.5mm 0.8mm |
10kΩ
10kΩ 10kΩ |
3380K
3380K 3380K |
3435K
3435K 3435K |
3453K
3453K 3453K |
729KB
|
39KB
|
98KB
|
|
|
NTCG06
NTCG10 NTCG16 NTCG20 |
0.6×0.3mm
[EIA 0201] 1.0×0.5mm [EIA 0402] 1.6×0.8mm [EIA 0603] 2.0×1.2mm [EIA 0805] |
0.3mm
0.5mm 0.8mm 1.0mm |
10kΩ～100kΩ
10kΩ～150kΩ 100Ω～150kΩ 10kΩ～100kΩ |
3380～4250K
3380～4533K 3244～4632K 3590～4085K |
3435～4308K
3435～4550K 3250～4720K 3590～4085K |
3453~4327K
3453~4573K 3251~4749K 3670~4172K |
455KB
|
|
|||
|
NTCSP10
NTCSP16 |
1.0×0.5mm
[EIA0402] 1.6×0.8mm [EIA0603] |
0.5mm
0.8mm |
10kΩ～100kΩ
10kΩ～100kΩ |
3380～4419K
3380～4419K |
3435～4485K
3435～4485K |
3453~4509K
3453~4509K |
289KB
|
|
|||
|
B57*V5
|
1.0×0.5mm
[EIA 0402] 1.6×0.8mm [EIA 0603] 2.0×1.25mm [EIA 0805] |
0.6mm max.
0.9mm max. 1.3mm max. |
4.7kΩ～100kΩ
10kΩ～100kΩ 4.7kΩ～100kΩ |
3940～4250K
3366～4386K 3590～4386K |
3980～4311K
3419～4455K 3635～4455K |
4000K±3%～4334K±1%
3439K±0.5%～4480K±3% 3650K±3%～4480K±3% |
445KB
|
209KB
|
209KB
|
|
|
|
B57621C5502H062
|
3.2×1.6mm
[EIA 1206] |
1.3mm max.
|
5.0kΩ
|
3375K
|
3420K
|
3455K
|
299KB
|
|
|||
|
B57*V6/C6 Soft termination
|
1.6×0.8mm
[EIA 0603] 3.2×1.6mm [EIA 1206] |
0.9mm max.
1.3mm max. |
10kΩ～47kΩ
5kΩ |
3380～4050K
3375K |
3435～4108K
3420K |
3455K±1%～4131K±1.5%
3455K±2% |
455KB
|
|
| Produktbild | Serien, Typen | Größe LxW | Bauhöhe | Nominaler Widerstand [bei 25°C) | B-Wert [25/50℃] |
B-Wert [25/85℃] |
B-Wert [25/100℃] |
Produkt-Katalog | RoHS-Zertifikat | REACH-Zertifikat | Bestell-nummern-Übersicht |
|---|---|---|---|---|---|---|---|---|---|---|---|
|
|
NTCGS06
NTCGS10 NTCGS16 |
0.6×0.3mm
[EIA 0201] 1.0×0.5mm [EIA 0402] 1.6×0.8mm [EIA 0603] |
0.3mm
0.5mm 0.8mm |
10kΩ
10kΩ 10kΩ |
3380K
3380K 3380K |
3435K
3435K 3435K |
3453K
3453K 3453K |
729KB
|
39KB
|
98KB
|
|
|
|
NTCG06
NTCG10 NTCG16 NTCG20 |
0.6×0.3mm
[EIA 0201] 1.0×0.5mm [EIA 0402] 1.6×0.8mm [EIA 0603] 2.0×1.2mm [EIA 0805] |
0.3mm
0.5mm 0.8mm 1.0mm |
10kΩ～100kΩ
10kΩ～150kΩ 100Ω～150kΩ 10kΩ～100kΩ |
3380～4250K
3380～4533K 3244～4632K 3590～4085K |
3435～4308K
3435～4550K 3250～4720K 3590～4085K |
3453~4327K
3453~4573K 3251~4749K 3670~4172K |
455KB
|
39KB
|
98KB
|
|
|
|
NTCSP10
NTCSP16 |
1.0×0.5mm
[EIA0402] 1.6×0.8mm [EIA0603] |
0.5mm
0.8mm |
10kΩ～100kΩ
10kΩ～100kΩ |
3380～4419K
3380～4419K |
3435～4485K
3435～4485K |
3453~4509K
3453~4509K |
289KB
|
39KB
|
98KB
|
|
|
|
B57*V5
|
1.0×0.5mm
[EIA 0402] 1.6×0.8mm [EIA 0603] 2.0×1.25mm [EIA 0805] |
0.6mm max.
0.9mm max. 1.3mm max. |
4.7kΩ～100kΩ
10kΩ～100kΩ 4.7kΩ～100kΩ |
3940～4250K
3366～4386K 3590～4386K |
3980～4311K
3419～4455K 3635～4455K |
4000K±3%～4334K±1%
3439K±0.5%～4480K±3% 3650K±3%～4480K±3% |
445KB
|
209KB
|
209KB
|
|
|
|
B57621C5502H062
|
3.2×1.6mm
[EIA 1206] |
1.3mm max.
|
5.0kΩ
|
3375K
|
3420K
|
3455K
|
299KB
|
209KB
|
209KB
|
|
|
|
B57*V6/C6 Soft termination
|
1.6×0.8mm
[EIA 0603] 3.2×1.6mm [EIA 1206] |
0.9mm max.
1.3mm max. |
10kΩ～47kΩ
5kΩ |
3380～4050K
3375K |
3435～4108K
3420K |
3455K±1%～4131K±1.5%
3455K±2% |
455KB
|
209KB
|
209KB
|
|
