Power NTC Thermistor Surge Current Limiter Nanjing Shiheng Elec MF72 5D7-3.5 Silicone Resin Encapsulation
Product Overview
The MF72 Power NTC Thermistor series from Nanjing Shiheng Electronics Co., Ltd. is designed for surge current limitation. These thermistors utilize a silicone resin encapsulation, offering high temperature resistance (up to 300C), efficient heat dissipation, and excellent insulation. While the silicone surface may exhibit minor friction marks and the encapsulation can be prone to slight cracks or chipping at the leads under improper handling, these aesthetic imperfections do not affect the product's performance or reliability. The MF72 series is suitable for applications requiring effective inrush current suppression.
Product Attributes
- Brand: Shiheng
- Product Type: Power NTC Thermistor
- Series: MF72
- Encapsulation Material: Green Silicone Resin
- Certifications: ISO9001:2015, IATF16949:2016, ISO14001:2015, RoHS 2.0, CQC (CQC04001010556), TUV (R50245892), UL (E241319), Jiangsu Province High-tech Product
- Origin: Nanjing, China
Technical Specifications
| Item | Symbol | Test Conditions | Unit | Requirements |
|---|---|---|---|---|
| Zero Power Resistance at 25 | R25 | Ta=250.5 (Test Power 0.1mW, in air) | 5 20% | |
| B-value (B25/50) | B | Ta=250.01, Tb=500.01 | K | 2600 10% |
| Max steady current | I max | - | A | 2 |
| Max allowable capacity value | CT | 240Vac | F | 150 |
| Thermal dissipation Coefficient | In still air | mW/ | 10 | |
| Thermal time constant | In still air | sec | 30 | |
| Withstand voltage | - | 500V/AC 1min | - | No breakthrough and flash over |
| Insulation resistance | - | 500V/DC 1min | M | 500 |
| Operating temperature range | - | - | -40 ~ 150 | |
| Maximum rated power | Pmax | - | W | 1 |
| Terminal strength (Pull strength) | - | 101 sec | N | 10 (for 0.5 |
| Solderability | - | Temperature 2455, time 2-3 sec | - | Tinning coverage area 95% |
| Withstand soldering temp | - | Tin pot temp: 2605, immersion depth 6mm from body, time 101 sec | - | |R25/25R|25% |
| Steady humidity and heat | - | Temp: 402, humidity: 932%, Time: 1000 hrs | - | |R25/25R|25% |
| Rapid changes in temperature | - | -40 30min 25 5min 150 30min 25 5min, 5 cycles | - | |R25/25R|25% |
| High temperature storage | - | Temp: 1505, Time: 1000 hrs | - | |R25/25R|25% |
| Durability for max steady current | - | Continuous application of max steady current at ambient temperature for 100024h | - | |R25/25R|25% |
| Max capacity value durability | - | 1000 cycles (intermittent switch 50ms, cut 5 times thermal time constant as one cycle) | - | |R25/25R|25% |
Product Dimensions (Unit: mm)
| D | L1 | L2 | T max | d |
|---|---|---|---|---|
| Max 8.0 | 3.50.5 | 5 | 5.0 | 0.60.05 |
Product Packaging
| Packing Type | Packing Specification | Packing Material, Size | Quantity |
|---|---|---|---|
| Bulk Type | Packing bag | Self sealing bag (WH11mm12mm) | - |
| Reel Type | Reel packing box | Packing box (WGH335mm240mm50mm) | - |
Installation & Use Precautions
- Purpose: Current limitation.
- Soldering: Weld spot should be at least 2mm from the head. Weld temperature below 360, time less than 3 seconds.
- Storage Temperature: -1040.
- Storage Humidity: 75% RH.
- Storage Environment: Avoid storage in environments with corrosive gases and illumination.
- Shelf Life: 1 year after opening the package. Products exceeding the storage period can be re-inspected according to the standard items and can still be used if they meet the requirements.
Material Description
The silicone resin encapsulation coating used for the MF72 Power NTC Thermistor offers high temperature resistance (above 300C), fast heat dissipation, and good insulation. The rough surface of the silicone resin aids in heat dissipation but may show friction marks from product contact; these marks do not affect performance and can be manually erased. While the material is firm, it is brittle. Improper handling such as heavy drops, bending leads outwards, or mismatching PCB hole pitch can cause cracks or chipping at the leads. These minor external defects have been proven through testing not to affect the product's performance or reliability.
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