NTC0805 Series 0402-Size Chip NTC Thermistors
The NYFEA NTC0805 Series comprises passive, two-terminal, surface-mount negative-temperature-coefficient thermistors in the 0805 imperial (2012 metric) size. The product specification lists nominal zero-power resistance at 25 °C (R25) values from 10 kΩ to 470 kΩ, R25 tolerance grades of ±1%, ±3%, or ±5% in the listed combinations, and part-specific B-constant characteristics.
Product scope: NTC0805 is a resistive sensing element, not a digital temperature-sensor IC or a self-contained protection device. The external system must provide controlled excitation, analog measurement, resistance-to-temperature conversion, calibration where required, suitable thermal coupling, diagnostics, and the final protection response.
Use the applicable controlled specification for purchasing, incoming inspection, PCB release, soldering approval and production qualification.
NTC0805 Product Overview and Scope
NTC0805 is a negative-temperature-coefficient sensing element whose resistance decreases as temperature increases. The compact 0805 package supports temperature measurement where PCB area is constrained, but pad geometry, solder symmetry, board flex, excitation power, copper heat spreading and nearby heat sources can materially affect the result.
| Selection question | NTC0805 specification | System-level decision |
|---|---|---|
| What component category is it? | Passive, two-terminal chip NTC thermistor. | Provide excitation, ADC measurement, conversion and fault handling externally. |
| Which nominal R25 values are listed? | 10 kΩ, 22 kΩ, 33 kΩ, 47 kΩ, 68 kΩ, 100 kΩ, 150 kΩ, 220 kΩ, 330 kΩ and 470 kΩ at 25 °C. | Select for ADC range, resolution, leakage, excitation power and temperature span. |
| Which R25 tolerances are listed? | F: ±1%; H: ±3%; J: ±5%. | The nine base configurations are listed in F, H and J grades; 150 kΩ, 220 kΩ, 330 kΩ and 470 kΩ are listed only in the J (±5%) table. |
| What are the thermal ratings? | 2.0 mW/°C dissipation factor; <5 s thermal time constant; 100 mW rated power at 25 °C. | Do not treat rated power as recommended measurement power. |
| What is the operating range? | −40 °C to +125 °C ambient. | Qualify the complete mounting, environment and mission profile. |
Ordering Codes and Part-Number Selection
Selection Highlights
- 0805 SMD format: 2.00 ±0.20 mm × 1.25 ±0.20 mm × 0.85 ±0.20 mm.
- Listed R25 values: 10 kΩ, 22 kΩ, 33 kΩ, 47 kΩ, 68 kΩ, 100 kΩ, 150 kΩ, 220 kΩ, 330 kΩ and 470 kΩ.
- R25 tolerance grades: ±1%, ±3% and ±5% in the combinations listed in the electrical tables.
- Thermal characteristics: <5 s thermal time constant and 2.0 mW/°C dissipation factor under the product-specification methods.
- Operating range: −40 °C to +125 °C ambient.
- Packing: paper carrier tape, 4,000 units per reel.
How to Read the Listed Part Numbers
| Field | Meaning | Values relevant to the listed NTC0805 range |
|---|---|---|
| NTC | Component category | Chip NTC thermistor |
| 0805 | External size code | 2.00 × 1.25 × 0.85 mm |
| X | Delimiter | Fixed delimiter in the ordering format |
| 103 / 223 / 333 / 473 / 683 / 104 / 154 / 224 / 334 / 474 | Nominal resistance code at 25 °C | 10 kΩ / 22 kΩ / 33 kΩ / 47 kΩ / 68 kΩ / 100 kΩ / 150 kΩ / 220 kΩ / 330 kΩ / 470 kΩ |
| F / H / J | R25 tolerance | ±1% / ±3% / ±5%; use only listed combinations |
| 3435 / 3450 / 3950 / 4050 / 4150 / 4250 | B-constant code | Interpret with the final A or B interval code |
| F | B-constant tolerance code | ±1% where explicitly shown |
| A / B | B calculation temperatures | A: 25 °C and 85 °C; B: 25 °C and 50 °C |
Part Numbers Listed in the Product Specification
The specification lists 31 complete orderable combinations. Values and tolerance placement below follow the electrical tables; an omitted B-value tolerance is not inferred.
| Listed part number | Nominal R25 and tolerance | B25/50 | B25/85 | Permissible current at 25 °C |
|---|---|---|---|---|
| NTC0805X103F3435FA | 10 kΩ ±1% | 3380 K ±1% | 3435 K ±1% | 0.44 mA |
| NTC0805X103F3450FB | 10 kΩ ±1% | 3450 K ±1% | 3500 K | 0.44 mA |
| NTC0805X103F3950FB | 10 kΩ ±1% | 3950 K ±1% | 3987 K | 0.44 mA |
| NTC0805X223F3950FB | 22 kΩ ±1% | 3950 K ±1% | 3987 K | 0.30 mA |
| NTC0805X333F4050FB | 33 kΩ ±1% | 4050 K ±1% | 4100 K | 0.24 mA |
| NTC0805X473F4050FB | 47 kΩ ±1% | 4050 K ±1% | 4100 K | 0.20 mA |
| NTC0805X683F4150FB | 68 kΩ ±1% | 4150 K ±1% | 4210 K | 0.16 mA |
| NTC0805X104F3950FB | 100 kΩ ±1% | 3950 K ±1% | 3987 K | 0.14 mA |
| NTC0805X104F4250FB | 100 kΩ ±1% | 4250 K ±1% | 4310 K | 0.14 mA |
| NTC0805X103H3435FA | 10 kΩ ±3% | 3380 K ±1% | 3435 K ±1% | 0.44 mA |
| NTC0805X103H3450FB | 10 kΩ ±3% | 3450 K ±1% | 3500 K | 0.44 mA |
| NTC0805X103H3950FB | 10 kΩ ±3% | 3950 K ±1% | 3987 K | 0.44 mA |
| NTC0805X223H3950FB | 22 kΩ ±3% | 3950 K ±1% | 3987 K | 0.30 mA |
| NTC0805X333H4050FB | 33 kΩ ±3% | 4050 K ±1% | 4100 K | 0.24 mA |
| NTC0805X473H4050FB | 47 kΩ ±3% | 4050 K ±1% | 4100 K | 0.20 mA |
| NTC0805X683H4150FB | 68 kΩ ±3% | 4150 K ±1% | 4210 K | 0.16 mA |
| NTC0805X104H3950FB | 100 kΩ ±3% | 3950 K ±1% | 3987 K | 0.14 mA |
| NTC0805X104H4250FB | 100 kΩ ±3% | 4250 K ±1% | 4310 K | 0.14 mA |
| NTC0805X103J3435FA | 10 kΩ ±5% | 3380 K ±1% | 3435 K ±1% | 0.44 mA |
| NTC0805X103J3450FB | 10 kΩ ±5% | 3450 K ±1% | 3500 K | 0.44 mA |
| NTC0805X103J3950FB | 10 kΩ ±5% | 3950 K ±1% | 3987 K | 0.44 mA |
| NTC0805X223J3950FB | 22 kΩ ±5% | 3950 K ±1% | 3987 K | 0.30 mA |
| NTC0805X333J4050FB | 33 kΩ ±5% | 4050 K ±1% | 4100 K | 0.24 mA |
| NTC0805X473J4050FB | 47 kΩ ±5% | 4050 K ±1% | 4100 K | 0.20 mA |
| NTC0805X683J4150FB | 68 kΩ ±5% | 4150 K ±1% | 4210 K | 0.16 mA |
| NTC0805X104J3950FB | 100 kΩ ±5% | 3950 K ±1% | 3987 K | 0.14 mA |
| NTC0805X104J4250FB | 100 kΩ ±5% | 4250 K ±1% | 4310 K | 0.14 mA |
| NTC0805X154J4250FB | 150 kΩ ±5% | 4250 K ±1% | 4310 K | 0.11 mA |
| NTC0805X224J3950FB | 220 kΩ ±5% | 3950 K ±1% | 3987 K | 0.08 mA |
| NTC0805X334J3950FB | 330 kΩ ±5% | 3950 K ±1% | 3987 K | 0.07 mA |
| NTC0805X474J3950FB | 470 kΩ ±5% | 3950 K ±1% | 3987 K | 0.05 mA |
Bracket notation used in the family summary is not an orderable code. Purchase and qualify a complete part number listed in the product specification.
NTC Principle, B-Constant Method, and R–T Approximation
NTC0805 has no digital interface. Its output is resistance, which the host circuit measures and converts to temperature using the exact part number's R25 and B data or a separately validated R–T lookup table.
Analog resistance
Two terminals; polarity independent for ordinary resistance measurement.
R25 at 25 °C
Nominal zero-power resistance is specified at 25 °C.
B constant
Use the calculation interval stated by the exact orderable code.
Host responsibility
ADC conversion, linearization, calibration, diagnostics and fault response are external.
For preliminary calculations, the B-parameter approximation is commonly written as R(T) = R25 × exp[B × (1/T − 1/T25)], with T and T25 in kelvin and T25 = 298.15 K. It is an engineering approximation over the interval associated with the stated B constant. Do not substitute B25/50 for B25/85 or treat one B value as a guaranteed full-range R–T curve.
Measurement Circuit, ADC Readout, and Fault Detection
The designer selects the excitation and readout topology to suit the resistance range, temperature span, ADC reference, measurement-uncertainty target, allowable self-heating, sample rate and required diagnostic coverage.
Excitation Power, Self-Heating, and Measurement Error
NTC0805 has no supply current or sleep mode. External excitation determines its power dissipation and the resulting self-heating error.
| Nominal R25 | Permissible operating current at 25 °C | Calculated I²R at nominal R25 | Specification definition |
|---|---|---|---|
| 10 kΩ | 0.44 mA | 1.94 mW | Current that produces a 1 °C body-temperature rise on the PCB in still air. |
| 22 kΩ | 0.30 mA | 1.98 mW | Current that produces a 1 °C body-temperature rise on the PCB in still air. |
| 33 kΩ | 0.24 mA | 1.90 mW | Current that produces a 1 °C body-temperature rise on the PCB in still air. |
| 47 kΩ | 0.20 mA | 1.88 mW | Current that produces a 1 °C body-temperature rise on the PCB in still air. |
| 68 kΩ | 0.16 mA | 1.74 mW | Current that produces a 1 °C body-temperature rise on the PCB in still air. |
| 100 kΩ | 0.14 mA | 1.96 mW | Current that produces a 1 °C body-temperature rise on the PCB in still air. |
| 150 kΩ | 0.11 mA | 1.81 mW | Current that produces a 1 °C body-temperature rise on the PCB in still air. |
| 220 kΩ | 0.08 mA | 1.41 mW | Current that produces a 1 °C body-temperature rise on the PCB in still air. |
| 330 kΩ | 0.07 mA | 1.62 mW | Current that produces a 1 °C body-temperature rise on the PCB in still air. |
| 470 kΩ | 0.05 mA | 1.18 mW | Current that produces a 1 °C body-temperature rise on the PCB in still air. |
I²R values are rounded calculations from nominal R25 and the listed permissible current; they are not additional guaranteed parameters. Where self-heating is material to the error budget, use lower continuous current or duty-cycled excitation and verify performance on the final PCB in the final enclosure.
Zero-Power Measurement Reference
The R25 method uses 25 ±0.05 °C and measurement power ≤0.1 mW. Calculate worst-case power across resistance, supply and component tolerances; do not confuse this test condition with a universal production-circuit setting.
Electrical Characteristics, Test Conditions, and Dimensions
Specification Test and Measurement Conditions
| Measurement or test | Condition stated in the product specification | Engineering interpretation |
|---|---|---|
| Standard atmospheric conditions | 20 ±15 °C; 65 ±20% RH; 86 kPa to 106 kPa | Applicable unless a different condition is specified. |
| Reference conditions if results are in doubt | 25 ±2 °C; 65 ±5% RH; 86 kPa to 106 kPa | Use these tighter limits to resolve disputed results. |
| Nominal zero-power resistance R25 | 25 ±0.05 °C; measuring power ≤0.1 mW | Characterization condition, not a production-circuit excitation recommendation. |
| Nominal B constant | Resistance at 25 ±0.05 °C and 50 ±0.05 °C or 85 ±0.05 °C | Use kelvin and the interval identified by the exact part number. |
Listed Electrical Configurations
| Nominal R25 | Listed part-number family | B25/50 | B25/85 | Permissible current at 25 °C |
|---|---|---|---|---|
| 10 kΩ | NTC0805X103[F/H/J]3435FA | 3380 K ±1% | 3435 K ±1% | 0.44 mA |
| 10 kΩ | NTC0805X103[F/H/J]3450FB | 3450 K ±1% | 3500 K | 0.44 mA |
| 10 kΩ | NTC0805X103[F/H/J]3950FB | 3950 K ±1% | 3987 K | 0.44 mA |
| 22 kΩ | NTC0805X223[F/H/J]3950FB | 3950 K ±1% | 3987 K | 0.30 mA |
| 33 kΩ | NTC0805X333[F/H/J]4050FB | 4050 K ±1% | 4100 K | 0.24 mA |
| 47 kΩ | NTC0805X473[F/H/J]4050FB | 4050 K ±1% | 4100 K | 0.20 mA |
| 68 kΩ | NTC0805X683[F/H/J]4150FB | 4150 K ±1% | 4210 K | 0.16 mA |
| 100 kΩ | NTC0805X104[F/H/J]3950FB | 3950 K ±1% | 3987 K | 0.14 mA |
| 100 kΩ | NTC0805X104[F/H/J]4250FB | 4250 K ±1% | 4310 K | 0.14 mA |
| 150 kΩ | NTC0805X154J4250FB | 4250 K ±1% | 4310 K | 0.11 mA |
| 220 kΩ | NTC0805X224J3950FB | 3950 K ±1% | 3987 K | 0.08 mA |
| 330 kΩ | NTC0805X334J3950FB | 3950 K ±1% | 3987 K | 0.07 mA |
| 470 kΩ | NTC0805X474J3950FB | 3950 K ±1% | 3987 K | 0.05 mA |
[F/H/J] denotes three listed R25-tolerance variants; [F/J] denotes the two variants listed for 470 kΩ. Brackets are not part of an orderable code. Tolerance placement follows the source table exactly.
| Parameter | Specified value | Condition or interpretation |
|---|---|---|
| Dissipation factor | 2.0 mW/°C | Power required to raise body temperature by 1 °C under the defined condition. |
| Thermal time constant | <5 s | 63.2% response under the specification method; not a finished-system guarantee. |
| Rated power | 100 mW at 25 °C | Specification definition corresponds to a 100 °C self-heating rise. |
| Operating ambient | −40 °C to +125 °C | Do not operate beyond this range. |
| Body length L | 2.00 ±0.20 mm | Controlled dimension |
| Body width W | 1.25 ±0.20 mm | Controlled dimension |
| Body thickness T | 0.85 ±0.20 mm | Controlled dimension |
| Terminal dimension a | 0.50 ±0.30 mm | Controlled dimension |
| Recommended land A | 1.00 to 1.10 mm | Dimension A in the drawing |
| Recommended land B / C | 0.60 to 0.70 mm / 1.00 to 1.20 mm | Validate paste aperture, placement and solder joints. |
PCB Land Pattern, Soldering, Reliability, Packing, and Storage
Reflow Soldering Window
- Ramp: 1 to 2 °C/s.
- Preheat: 150 to 170 °C for 90 ±30 s.
- Time above 240 °C: 20 to 40 s.
- Peak: 260 °C maximum for 10 s.
- Maximum reflow cycles: two.
- Specified solder: 96.5Sn / 3.0Ag / 0.5Cu.
Manual Soldering Boundary
The specification limits the iron to 20 W, requires preheating at 150 °C for 60 s, limits the tip to 280 °C and 3 s, and permits one operation. Do not touch the terminal electrodes with the tip.
Reliability Test Conditions
| Test | Condition | Requirement shown in the specification |
|---|---|---|
| Terminal strength | 5 N for 10 ±1 s | No terminal removal, ceramic split or other defect. |
| Board flexure | 2 mm; press speed <0.5 mm/s; 10 ±1 s | No visible damage; |ΔR25/R25| ≤2%. |
| Vibration | 10–55 Hz; 1.5 mm total amplitude; 2 h in each of three axes | No visible damage. |
| Drop | 1 m onto concrete, 10 times | No visible damage. |
| Solderability | 245 ±5 °C for 3 ±0.3 s | At least 95% wetting coverage. |
| Soldering heat | 260 ±5 °C for 10 ±1 s | No visible damage; |ΔR25/R25| ≤2%; |ΔB/B| ≤1%. |
| Temperature cycling | Five cycles: −40 ±5 °C / 25 ±2 °C / 125 ±2 °C / 25 ±2 °C with specified dwell times | No visible damage; |ΔR25/R25| ≤2%; |ΔB/B| ≤1%. |
| Dry heat / cold storage | 125 ±5 °C for 1000 ±24 h / −40 ±3 °C for 1000 ±24 h | No visible damage; |ΔR25/R25| ≤2%; |ΔB/B| ≤1%. |
| Damp heat | 40 ±2 °C; 90% to 95% RH; 1000 ±24 h | No visible damage; |ΔR25/R25| ≤2%; |ΔB/B| ≤1%. |
| High-temperature load | 85 ±2 °C; permissible current; 1000 ±48 h | No visible damage; |ΔR25/R25| ≤2%; |ΔB/B| ≤1%. |
Where specified, stabilize samples for 1 to 2 hours under normal conditions before measurement.
Packing and Storage
NTC0805 is supplied on 8.0 ±0.3 mm paper carrier tape, 4,000 units per reel. Tape thickness is 0.5 ±0.15 mm; component pitch is 4.0 ±0.1 mm. The reel outer diameter is 178 ±2 mm and hub diameter is 58 ±2 mm. Store at −10 °C to +40 °C and ≤75% RH, protected from dust, corrosive atmosphere and direct sunlight. The stated storage period is six months.
Application Guidance and Design Limitations
The specification does not grant application-specific approval. The following are potential categories requiring complete circuit, thermal, mechanical, environmental, assembly and safety qualification.
Compact PCB temperature sensingValidate heat spreading, local hot spots, solder symmetry and the offset between board and target temperature.
Battery and power monitoringDefine the thermal interface and diagnostics. The thermistor alone does not disconnect power or provide a certified safety function.
Portable and space-constrained electronicsQualify moisture protection, board flex, handling and excitation duty cycle in the final product.
Temperature compensationUse a validated R–T model, placement and calibration that satisfy the circuit error budget.NTC0805 Engineering FAQs
What is the NTC0805 Series?
NTC0805 is a passive, two-terminal surface-mount NTC thermistor series in a 0805 imperial / 2012 metric body. Resistance decreases as temperature increases.
What does 0805 mean?
0805 is the imperial package designation; the corresponding metric designation is 2012. Use the controlled dimensions and tolerances for PCB design.
Is NTC0805 a digital temperature sensor?
No. It has no supply pin, address, digital protocol, register map or digital output. The external circuit measures resistance and converts it to temperature.
Which NTC0805 resistance values are listed?
The specification lists 10 kΩ, 22 kΩ, 33 kΩ, 47 kΩ, 68 kΩ, 100 kΩ, 150 kΩ, 220 kΩ, 330 kΩ and 470 kΩ nominal R25 values. Use a complete listed part number because B characteristics and tolerance combinations differ.
Which B constant should be used?
Use the B value and temperature interval assigned to the exact listed part number. Do not interchange B25/50 and B25/85 or treat one B value as a guaranteed full-range R–T curve.
How are R25 and the B constant measured?
R25 is measured at 25 ±0.05 °C with measuring power ≤0.1 mW. B is calculated from resistance at 25 ±0.05 °C and at either 50 ±0.05 °C or 85 ±0.05 °C.
What is the permissible operating current?
The listed values range from 0.44 mA to 0.05 mA. The specification defines this current by a 1 °C self-heating rise on the PCB in still air; it is not a universal recommended measurement current.
What is the specified NTC0805 thermal time constant?
The product specification lists less than 5 s under its stated 63.2% response definition. Finished-product response also depends on PCB copper, solder, coating, airflow and thermal contact.
Can the 100 mW rated power be used as measurement power?
No. It is a rated-power definition, not a recommended excitation level. Select measurement power from the allowable self-heating error.
Can it replace another thermistor with the same package and R25?
Not automatically. Match R25 tolerance, B value and interval, R–T behavior, power and current limits, dimensions, land pattern, assembly process and qualification requirements.
What reflow profile is specified?
The specification lists a 1–2 °C/s ramp, 150–170 °C preheat for 90 ±30 s, 20–40 s above 240 °C and a maximum 260 °C peak for 10 s, with no more than two reflow cycles.
How is NTC0805 packed and stored?
Paper tape contains 4,000 parts per reel. Store at −10 °C to +40 °C and ≤75% RH, away from dust, corrosive atmosphere and sunlight; the specified storage period is six months.
This page summarizes the NYFEA NTC0805 Series product specification for selection and engineering evaluation. It does not replace the controlled PDF. Confirm the exact part number, ratings, test conditions, dimensions, soldering, packing and application qualification before production release.
