# MF11 Series NTC Thermistors for Temperature Compensation

> Radial dipped NTC thermistors for circuit temperature compensation and general temperature measurement. R25 5 Ω–500 kΩ, B25/50 2,600–4,750 K, operating temperature −30 °C to +125 °C.

- Series code: MF11
- Product line: [Thermistors (NTC / PTC)](https://www.songtian-ste.com/en/products/thermistors/) › NTC thermistors for temperature sensing and compensation
- Part numbers: Part-number list on request
- Page: https://www.songtian-ste.com/en/products/ntc-thermistors/mf11/
- Chinese version: https://www.songtian-ste.com/zh/products/ntc-thermistors/mf11/
- [Ask AI about this series](https://www.songtian-ste.com/en/products/ntc-thermistors/mf11/?ask=Help%20me%20choose%20a%20part%20from%20the%20STE%20MF11%20series.)

## Key specifications

| Parameter | Value |
| --- | --- |
| R25 | 5 Ω–500 kΩ |
| B25/50 | 2,600–4,750 K |
| B-value tolerance | ±10% |
| R25 tolerance | ±5% to ±20% |
| Operating temperature | −30 °C to +125 °C |
| Body size | 6.5 × 4.0 mm max. |

## Engineering details

### Overview

Radial dipped NTC thermistors for general temperature measurement and circuit temperature compensation. 14 B25/50 curves from 2,600 K to 4,750 K cover R25 5 Ω–500 kΩ; B-value tolerance ±10%. Body max. 6.5 mm wide and 4.0 mm thick. Operating temperature −30 °C to +125 °C.

#### Series features

- 14 B25/50 curves from 2,600 K to 4,750 K
- R25 from 5 Ω to 500 kΩ
- Compact radial outline: max. 6.5 mm wide, max. 4.0 mm thick
- Wave-soldering and hand-soldering conditions specified

#### Typical applications

- General temperature measurement
- Temperature compensation in metering and measurement equipment
- Bias, gain, oscillator and semiconductor compensation in electronic circuits
- PCB-mounted ambient or component temperature sensing
- Analog linearization networks
- Industrial and consumer electronics

### Specifications

|   |   |
| --- | --- |
| Function | Radial NTC thermistor for general temperature measurement and circuit temperature compensation |
| Environmental compliance | RoHS and REACH compliant; halogen status and material declarations on request |
| Packing | Bulk or taped |
| B25/50 curves | 14 curves, each covering one R25 range |
| B25/50 range | 2,600–4,750 K |
| B-value tolerance | ±10% |
| R25 range | 5 Ω–500 kΩ |
| Curve B25/50 2,600 K | R25 5–7 Ω |
| Curve B25/50 2,800 K | R25 8–24 Ω |
| Curve B25/50 3,000 K | R25 25–119 Ω |
| Curve B25/50 3,200 K | R25 120–359 Ω |
| Curve B25/50 3,600 K | R25 360–1,400 Ω |
| Curve B25/50 3,950 K | R25 1,500–5,900 Ω |
| Curve B25/50 4,050 K | R25 6,000–12,000 Ω |
| Curve B25/50 4,150 K | R25 13,000–17,000 Ω |
| Curve B25/50 4,300 K | R25 45,000–79,000 Ω |
| Curve B25/50 4,400 K | R25 80,000–144,000 Ω |
| Curve B25/50 4,500 K | R25 145,000–199,000 Ω |
| Curve B25/50 4,600 K | R25 200,000–299,000 Ω |
| Curve B25/50 4,750 K | R25 300,000–500,000 Ω |
| R25 tolerance | ±5% · ±10% · ±15% · ±20%; tolerances available per curve on request |
| Available values | R25 ranges are curve bands, not individual part numbers. |
| Temperature accuracy | R25 and B tolerances do not state a ±°C accuracy. Calculate the temperature error from the R/T table of the selected part number. |
| Zero-power resistance | DC resistance at temperature t, measured at a power low enough that any further reduction changes the resistance by less than 0.1% |
| Operating temperature | −30 °C to +125 °C |
| Thermal time constant | Approx. 30 s |
| Dissipation constant | Approx. 4.5 mW/°C |
| Body width | 6.5 mm max. |
| Body thickness | 4.0 mm max. |
| Lead spacing | 2.5 ±1.0 mm |
| Lead diameter | 0.45 mm (nom.) |
| Lead length | ≥25 mm from the body |
| Coating | Dipped coating |
| Coating insulation | No insulation rating is specified for the coating. Qualify it before relying on it for isolation. |
| Wave soldering, preheat | Ambient to 130 ±20 °C in 30–90 s; 1–3 °C/s |
| Wave soldering, ramp to peak | 130 ±20 °C to 260 °C max. in <1 s (approx. 200 °C/s) |
| Wave soldering, dwell | <10 s at peak |
| Wave soldering, cooling | 5 °C/s max. |
| Hand soldering and rework | Iron tip 300 °C max. · 3 s max. · joint at least 2 mm from the coating |
| Handling | Do not touch the thermistor while it is energized. |
| Storage | ≤35 °C · ≤70% RH · 12 months · keep the original package closed and reseal after opening |
| Corrosive atmospheres | Hydrogen chloride, hydrogen sulfide and sulfur compounds can degrade terminal solderability. Avoid exposure. |
| Further data | On request: nominal R25, B value, tolerance and resistance–temperature (R/T) table of each part number · measuring medium and conditions for the thermal time constant and dissipation constant · max. power at 25 °C, power derating, max. measuring current and voltage, allowed self-heating · max. working voltage, insulation resistance and dielectric withstand · coating material, flammability and insulation properties · lead alloy, plating and solderability class · recommended PCB hole pattern · packing method, quantity and taping dimensions · wave-soldering solder alloy, immersion depth and number of cycles · post-solder resistance limits, cleaning compatibility, lead forming and conformal-coating or potting compatibility · load-life, high- and low-temperature storage, thermal-shock, damp-heat, vibration, lead-strength, solderability and long-term drift results · temperature coefficient α, linearization range and example compensation networks |

### Variants

Ranges by dielectric, package and lead style within this series.

| Variant | Body dimensions | R25 range | Tolerance | Lead / land pattern | Notes |
| --- | --- | --- | --- | --- | --- |
| B25/50 2600 K | 6.5 max. × 4.0 max. mm, radial | R25 5–7 Ω | B ±10%; R25 tolerance per part number | Leads Ø0.45 mm · spacing 2.5 ±1 mm · ≥25 mm long | Very low resistance, for low-ohm compensation. |
| B25/50 2800 K | Same outline | R25 8–24 Ω | B ±10%; R25 tolerance per part number | Same leads | Low resistance, low B value. |
| B25/50 3000 K | Same outline | R25 25–119 Ω | B ±10%; R25 tolerance per part number | Same leads | Low-resistance compensation. |
| B25/50 3200 K | Same outline | R25 120–359 Ω | B ±10%; R25 tolerance per part number | Same leads | Sub-kilohm compensation. |
| B25/50 3600 K | Same outline | R25 360–1,400 Ω | B ±10%; R25 tolerance per part number | Same leads | Low-kilohm compensation. |
| B25/50 3950 K | Same outline | R25 1.5–5.9 kΩ | B ±10%; R25 tolerance per part number | Same leads | Mid B value. Select the nominal R25 and R/T data. |
| B25/50 4050 K | Same outline | R25 6–12 kΩ | B ±10%; R25 tolerance per part number | Same leads | Nominal 10 kΩ region. |
| B25/50 4150 K | Same outline | R25 13–17 kΩ | B ±10%; R25 tolerance per part number | Same leads | Higher sensitivity. |
| B25/50 4300 K | Same outline | R25 45–79 kΩ | B ±10%; R25 tolerance per part number | Same leads | High-resistance compensation. |
| B25/50 4400 K | Same outline | R25 80–144 kΩ | B ±10%; R25 tolerance per part number | Same leads | High-resistance compensation. |
| B25/50 4500 K | Same outline | R25 145–199 kΩ | B ±10%; R25 tolerance per part number | Same leads | High B value. |
| B25/50 4600 K | Same outline | R25 200–299 kΩ | B ±10%; R25 tolerance per part number | Same leads | High resistance, high B value. |
| B25/50 4750 K | Same outline | R25 300–500 kΩ | B ±10%; R25 tolerance per part number | Same leads | Highest R25 and B value. Check leakage and noise in the circuit. |

### Selection guide

Start with the compensation interval, the permitted residual error of the circuit and the thermal location. Then select nominal R25, B25/50 and tolerance, and design with the R/T data, excitation limits and construction details of the selected part.

1. **Define the compensation target and error budget**
   Specify temperature interval, nominal compensation point, required residual error, source impedance, ADC and reference or analog network, response, self-heating, life, humidity and the thermal and mechanical PCB environment.
2. **Select the curve**
   Choose nominal R25 and B25/50 from the 14 curves. Evaluate the R/T table (min./typ./max.), temperature coefficient, temperature error, interpolation and drift of the selected part number.
3. **Calculate excitation and thermal coupling**
   Use the full curve to limit current, voltage, power and self-heating at every temperature. Correlate the approx. 30 s and 4.5 mW/°C values with the actual PCB location, airflow and lead heat path.
4. **Specify construction, footprint and assembly**
   Define coating and insulation, lead alloy and plating, body and lead tolerances, hole pattern, packing, forming limits and the wave- or hand-soldering, cleaning and coating process.
5. **Qualify the part in the circuit**
   Validate curve accuracy, compensation residual, power derating, humidity with bias, dry heat, thermal cycling and shock, vibration, lead strength, solderability, process shift and long-term drift.

### Design notes

#### Design from R/T limits, not nominal B alone

The compensation residual depends on the full curve and its tolerances over the target interval. Obtain min./typ./max. R/T data or coefficients and model the actual network, reference and ADC errors.

#### Include self-heating in the error budget

Obtain the rated power and measuring current of the selected part. Calculate the excitation at worst-case resistance and temperature, use duty cycling where possible and verify the body temperature rise on the board.

#### Qualify the coating before relying on it

The dipped coating has no specified insulation, flammability or potting-compatibility rating. Obtain coating and lead materials and qualify humidity, cleaning, conformal coating and electrical isolation.

#### Use the wave-soldering profile as a limit

Validate solder alloy, flux, board, immersion depth, preheat, 260 °C peak, <10 s dwell, cooling, lead forming and post-solder R/T shift for the packed part.

#### Define packing before automated insertion

Define carrier pitch, orientation and quantity or bulk insertion controls, hole pattern, seating plane, lead form and marking before production.

## Datasheets & approval documents

- [Technical document: MF11 series NTC thermistors for temperature compensation](https://www.songtian-ste.com/documents/source-cn/%E8%B4%9F%E6%B8%A9%E5%BA%A6%E7%B3%BB%E6%95%B0%E7%83%AD%E6%95%8F%E7%94%B5%E9%98%BB%E5%99%A8-MF11%E6%B8%A9%E5%BA%A6%E8%A1%A5%E5%81%BF%E5%9E%8B%E7%B3%BB%E5%88%97.pdf) — PDF · Chinese · 284 KB

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