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Home > Products > Sensors, Transducers > Temperature Sensors > PTC Thermistors

NXP Semiconductors KTY81/210,116

Name: KTY81/210,116
Brand: NXP Semiconductors
SKU: KTY81/210,116
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KTY81/210,116

Manufacturer:: NXP Semiconductors

Category:: PTC Thermistors

Package:: TO-226-2, TO-92-2 (TO-226AC)

Datasheet:: KTY81/210,116.pdf

Description:: SENSOR PTC 2KOHM PBCYT2

Quantity:: RFQ Add To RFQ list

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Inventory:1,955

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Product details

Overview

KTY81/210,116 from NXP Semiconductors is a silicon-based positive temperature coefficient (PTC) temperature sensor in SOD70 plastic package, with nominal resistance of 2000 Ω at 25 °C, ±0.79 %/K temperature coefficient, and operating range from −55 °C to +150 °C. It delivers stable resistance-vs-temperature linearity for HVAC airflow monitoring, motor winding thermal protection, and industrial oven temperature feedback.

For engineers reviewing the KTY81/210,116 datasheet, KTY81/210,116 pinout, KTY81/210,116 application, or KTY81/210,116 equivalent, this page provides verified resistance values across −55 °C to 150 °C, thermal time constants in air/liquid, long-term drift specification, fail-safe PTC behavior, and direct alternative part comparisons for thermal sensing circuit redesign.

Technical Context

The KTY81/210,116 operates as a two-terminal passive resistive element requiring external bias current (recommended 1 mA) to generate voltage proportional to temperature. Its PTC response ensures monotonic, predictable resistance increase with rising ambient temperature - eliminating ambiguity in fault detection scenarios.

Resistance variation follows a well-characterized curve with R₁₀₀/R₂₅ = 1.696 and R₋₅₅/R₂₅ = 0.490, enabling accurate linearization via lookup tables or polynomial compensation. Thermal time constant is 30 s in still air and 3 s in flowing liquid, defining dynamic response limits for closed-loop control timing.

Key Specifications

Parameter	Value and Actual Design Meaning
R₂₅	1980–2020 Ω at 25 °C; defines baseline scaling for analog-to-temperature conversion circuits
Temperature Coefficient	0.79 %/K typical; enables predictable resistance change per degree for calibration-free designs
R₁₀₀/R₂₅	1.676–1.716; quantifies resistance ratio between 100 °C and 25 °C for high-temp accuracy validation
Operating Range	−55 °C to +150 °C; supports under-hood automotive, industrial motor, and power supply thermal monitoring
Max Continuous Current	10 mA at 25 °C; sets upper limit for excitation current to avoid self-heating error & drift
Thermal Time Constant	30 s in still air; determines minimum sampling interval for transient temperature tracking
Long-Term Drift	≤3.2 Ω after 10,000 h at 150 °C; guarantees stability in continuous high-temp operation

Pinout & Package

Package: SOD70 - near-cylindrical plastic case with two inline leads, 2.54 mm lead pitch (bulk), 5.08 mm spread lead pitch (reel), body dimensions 4.4–4.8 mm wide × 5.0–5.2 mm high × 3.6–4.2 mm thick.

Pin/Terminal	Circuit Role	Design Meaning
1	Electrical contact	Unpolarized terminal; connects to bias current source or voltage divider node
2	Electrical contact	Unpolarized terminal; completes current path; no functional distinction from Pin 1

Key Features

Feature	Design Value
Positive Temperature Coefficient (PTC)	Fail-safe behavior: resistance increases with temperature, preventing undetected overtemperature failure
Virtually Linear Characteristics	±1.27 K max temperature error at 25 °C enables simple 2-point calibration for <±2 K system accuracy
Long-Term Stability	Drift ≤3.2 Ω after 10,000 h at 150 °C supports 10+ year reliability in sealed industrial enclosures
ESD-Sensitive Construction	Requires handling per IEC 61000-4-2 Level 2; avoids gate oxide damage during PCB assembly
Wide Operating Range	−55 °C to +150 °C ambient rating allows direct mounting on heatsinks, motors, and power semiconductors

Applications

Motor Winding Protection	HVAC Airflow Sensing
Use Scenario: Embedded inside stator windings of industrial AC motors to detect thermal overload before insulation breakdown. IC Role / Device Role / Timing Role: Passive resistive temperature transducer; no timing role; provides analog resistance signal to comparator or ADC. Use Value: PTC behavior ensures resistance rises predictably with winding temperature, triggering shutdown before irreversible damage occurs.	Use Scenario: Mounted in ductwork upstream of heat exchangers to monitor supply air temperature for PID-controlled fan speed modulation. IC Role / Device Role / Timing Role: Analog temperature sensing element; interfaces with microcontroller ADC via simple voltage divider. Use Value: 30 s thermal time constant in air matches HVAC thermal mass dynamics, avoiding false alarms from transient airflow pulses.
Oven Temperature Feedback	Power Supply Thermal Monitoring
Use Scenario: Surface-mounted on heating element brackets in commercial convection ovens to regulate setpoint accuracy within ±2 °C. IC Role / Device Role / Timing Role: Two-terminal analog sensor; no active circuitry; requires external 1 mA bias for linear response. Use Value: R₁₀₀/R₂₅ = 1.696 enables precise polynomial compensation to meet IEC 60519 Class B oven calibration requirements.	Use Scenario: Attached to MOSFET heatsink in telecom DC-DC converters to throttle output power before thermal shutdown. IC Role / Device Role / Timing Role: Fail-safe thermal sentinel; resistance increase directly correlates with junction temperature rise. Use Value: 150 °C max ambient rating allows direct placement on thermally coupled surfaces without derating.

Motor Winding Protection

HVAC Airflow Sensing

Use Scenario: Embedded inside stator windings of industrial AC motors to detect thermal overload before insulation breakdown.

IC Role / Device Role / Timing Role: Passive resistive temperature transducer; no timing role; provides analog resistance signal to comparator or ADC.

Use Value: PTC behavior ensures resistance rises predictably with winding temperature, triggering shutdown before irreversible damage occurs.

Use Scenario: Mounted in ductwork upstream of heat exchangers to monitor supply air temperature for PID-controlled fan speed modulation.

IC Role / Device Role / Timing Role: Analog temperature sensing element; interfaces with microcontroller ADC via simple voltage divider.

Use Value: 30 s thermal time constant in air matches HVAC thermal mass dynamics, avoiding false alarms from transient airflow pulses.

Oven Temperature Feedback

Power Supply Thermal Monitoring

Use Scenario: Surface-mounted on heating element brackets in commercial convection ovens to regulate setpoint accuracy within ±2 °C.

IC Role / Device Role / Timing Role: Two-terminal analog sensor; no active circuitry; requires external 1 mA bias for linear response.

Use Value: R₁₀₀/R₂₅ = 1.696 enables precise polynomial compensation to meet IEC 60519 Class B oven calibration requirements.

Use Scenario: Attached to MOSFET heatsink in telecom DC-DC converters to throttle output power before thermal shutdown.

IC Role / Device Role / Timing Role: Fail-safe thermal sentinel; resistance increase directly correlates with junction temperature rise.

Use Value: 150 °C max ambient rating allows direct placement on thermally coupled surfaces without derating.

Equivalent & Alternatives

The following parts are listed as comparable options for similar silicon PTC temperature sensing applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
KTY81/220	Same SOD70 package; R₂₅ = 1960–2040 Ω; identical TC and R₁₀₀/R₂₅ spec	No functional difference; used where tighter initial tolerance not required	Select when ±20 Ω R₂₅ tolerance is acceptable versus KTY81/210,116's ±20 Ω window centered at 2000 Ω
TSI301-2000	Different SOT-23-3 package; 2000 Ω ±1 % at 25 °C; integrated ESD protection; higher cost	Requires PCB layout change; offers better initial accuracy but less rugged mechanical form factor	Choose only if 1 % R₂₅ tolerance and surface-mount compatibility outweigh SOD70's axial-leaded robustness

Compared with KTY81/210,116, KTY81/220 offers identical thermal performance with looser R₂₅ bounds, while TSI301-2000 trades mechanical ruggedness for tighter tolerance and SMT fit - making KTY81/210,116 optimal for cost-sensitive, high-reliability axial-leaded thermal monitoring.

Availability

KTY81/210,116 is available at Aetrix Electronics and suitable for HVAC airflow sensing, motor winding protection, and oven temperature feedback requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for KTY81/210,116 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

NXP Semiconductors is a global semiconductor company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and IoT applications.

The KTY81 series was designed by NXP as low-cost, high-stability silicon PTC sensors targeting thermal protection and measurement in harsh environments where ceramic or thermistor alternatives lack long-term drift performance.

FAQ

What is the recommended operating current for KTY81/210,116 to minimize self-heating error?

The recommended continuous operating current for KTY81/210,116 is 1 mA, as specified in the datasheet for all resistance and temperature error measurements. At this level, self-heating remains below 0.1 K in still air, preserving measurement accuracy. Exceeding 10 mA at 25 °C risks permanent drift; KTY81/210,116 must be biased within its absolute maximum ratings to maintain long-term stability.

Does KTY81/210,116 require polarity-aware connection in circuit?

No, KTY81/210,116 is a two-terminal passive resistor with no polarity; Pins 1 and 2 are electrically identical and interchangeable. The device functions identically regardless of orientation in a voltage divider or constant-current bias configuration. This simplifies PCB layout and eliminates risk of reverse installation - a key advantage over diode-based or IC temperature sensors.

How does the temperature coefficient of KTY81/210,116 compare to NTC thermistors in practical use?

KTY81/210,116 has a positive temperature coefficient of 0.79 %/K, meaning resistance increases predictably with temperature - unlike NTC thermistors whose resistance drops nonlinearly. This PTC behavior provides inherent fail-safe detection: open-circuit or wiring fault yields infinite resistance (interpreted as overtemperature), whereas NTC faults may mimic normal cold-state readings. KTY81/210,116 thus reduces system-level diagnostic complexity.

Can KTY81/210,116 be used in reflow soldering processes?

KTY81/210,116 is qualified for wave soldering and hand-soldering per its SOD70 package specifications, but is not rated for standard Pb-free reflow profiles (e.g., JEDEC J-STD-020). Peak temperatures above 260 °C risk internal bond degradation. For automated assembly, selective soldering or adhesive mounting followed by hand-soldering of leads is recommended to preserve KTY81/210,116's long-term drift performance and mechanical integrity.

What is the maximum expected temperature error of KTY81/210,116 at 100 °C?

At 100 °C, the maximum expected temperature error for KTY81/210,116 is ±3.46 K when operated at 1 mA, as documented in Table 10 of the NXP datasheet. This error includes contributions from resistance tolerance, nonlinearity, and thermal time constant effects. For applications requiring tighter accuracy, polynomial compensation using R₁₀₀/R₂₅ = 1.696 and R₋₅₅/R₂₅ = 0.490 can reduce residual error to <±1 K across −20 °C to 120 °C.

KTY81/210,116 Specifications

Product attributes: Attribute value

Manufacturer:: NXP Semiconductors

Series:: KTY81

Package/Case:: TO-226-2, TO-92-2 (TO-226AC)

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Resistance @ 25°C:: 2 kOhms

Resistance Tolerance:: -

Operating Temperature:: -55°C ~ 150°C

Power - Max:: -

Mounting Type:: Through Hole

Grade:: -

Qualification:: -

Supplier Device Package:: PBCYT2

KTY81/210,116 FAQ

1.How can I place an order for KTY81/210,116 through Aetrix?

Please submit a Request for Quotation (RFQ) for KTY81/210,116 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for KTY81/210,116 reliable?

The price and inventory of KTY81/210,116 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KTY81/210,116 is usually 5 days.

3.What payment methods are accepted for KTY81/210,116?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KTY81/210,116 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KTY81/210,116?

KTY81/210,116 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KTY81/210,116 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for KTY81/210,116?

For technical support, including KTY81/210,116 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KTY81/210,116 requirements.

6.How does Aetrix verify that KTY81/210,116 is sourced from the original manufacturer or authorized distributors?

All KTY81/210,116 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that KTY81/210,116 meets industry standards.

7.What is the process for return or replacement of KTY81/210,116?

All KTY81/210,116 units undergo pre-shipment inspection (PSI). If there is an issue with KTY81/210,116, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The KTY81/210,116 part is unused and in its original packaging.

Return procedure for KTY81/210,116:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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