Directly heated negative temperature coefficient thermistors - Sectional specification. Surface mount negative temperature coefficient thermistors
1Key Takeaways
What is BS EN IEC 60539-2 - Negative temperature coefficient thermistors about ? BS EN IEC 60539-2 is an international standard used for directly heated negative temperature coefficient thermistors. BS EN IEC 60539-2 specifies the test methods. BS EN IEC 60539 ‑ 2 is applicable t…
2Expert Interpretation
BS EN IEC 60539-2:2019 specifies in detail the technical requirements, test methods and quality assessment procedures for direct-heated negative temperature coefficient (NTC) surface mount thermistors. This standard applies to thermistors made of transition metal oxide semiconductor materials, including key parameters such as dimensional specifications, electrical characteristics, and environmental testing. It is an important basis for the design and selection of temperature control components for electronic equipment.
Interpretation of the core content of the standard
| Technical parameters | 2004 edition | 2019 edition update |
|---|---|---|
| Operating temperature range | -55°C~150°C | Extended to -55°C~400°C |
| Dimension specifications | 5 package sizes | New 0402M ultra-small package |
| Moisture resistance test cycle | Maximum 42 days | Add56 days of stringent conditions |
Key test requirements
Surface mount NTC thermistors must pass the following core tests:
- Visual inspection: Cracks in the ceramic body must not exceed 25% of the length under a 10x magnifying glass
- Soldering heat resistance: Resistance change after 260°C reflow soldering ≤±5%
- Temperature cycling: No mechanical damage after 5 cycles from -55°C to upper limit temperature
- Durability test: Resistance stability requirement after 1000 hours of high temperature aging
Technology evolution analysis
The main technical innovations of the 2019 version are:
- New automotive-grade high-temperature specifications (175°C/200°C/250°C/315°C/400°C)
- Introduction of the latest welding test method of IEC 60068-2-58:2015
- Strengthening the delamination detection requirements for stacked structure devices
Implementation Recommendations
Special attention should be paid to the following when designing and applying:
| 1. Pad design | Should meet the L4 minimum size requirements in Table A.1 |
| 2. Process control | The dissolution of the terminal plating shall not exceed 25% of the edge length |
| 3. Reliability Verification | It is recommended to add substrate bending test (Clause 7.13) |