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

NXP Semiconductors KTY81/110,116

Name: KTY81/110,116
Brand: NXP Semiconductors
SKU: KTY81/110,116
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KTY81/110,116

Manufacturer:: NXP Semiconductors

Category:: PTC Thermistors

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

Datasheet:: KTY81/110,116.pdf

Description:: SENSOR PTC 1KOHM PBCYT2

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Product details

Overview

KTY81/110,116 from NXP Semiconductors is a silicon-based positive temperature coefficient (PTC) temperature sensor in SOD70 plastic package, designed for precision analog temperature measurement in liquid or still-air environments. It delivers 990–1010 Ω resistance at 25 °C, 0.79 %/K temperature coefficient, ±1.27 K max error at 25 °C, and operates across −55 to +150 °C ambient range - used in HVAC sensor modules, motor winding thermal protection, and industrial process control feedback loops.

For engineers reviewing the KTY81/110,116 datasheet, KTY81/110,116 pinout, KTY81/110,116 application, or KTY81/110,116 equivalent, this page provides verified electrical characteristics, thermal time constant data (5 s in liquid), resistance vs. temperature tables, fail-safe PTC behavior, and direct substitution guidance for embedded thermal monitoring designs requiring linear analog output and long-term drift stability.

Technical Context

The KTY81/110,116 functions as a two-terminal resistive transducer whose resistance increases predictably with temperature. Its PTC response is derived from bulk silicon properties, not doped thermistors, enabling virtually linear R–T behavior over −40 to +125 °C (R₁₀₀/R₂₅ = 1.676–1.716) and intrinsic fail-safe operation - open-circuit failure mode raises resistance, signaling fault in series-monitoring circuits.

It requires a stable 1 mA excitation current for specified accuracy; self-heating is minimized by limiting continuous current to 10 mA at 25 °C and 2 mA at 150 °C. Thermal time constant is 5 s in flowing liquid and 30 s in still air, defining dynamic response limits in closed-loop thermal regulation systems.

Key Specifications

Parameter	Value and Actual Design Meaning
R₂₅	990–1010 Ω at 25 °C with 1 mA bias - sets baseline gain and offset calibration point for analog front-end circuitry
Temperature coefficient	0.79 %/K typical - enables direct voltage-to-temperature conversion using fixed-resistor divider without complex linearization
R₁₀₀/R₂₅	1.676–1.716 - defines usable linear range up to 100 °C; supports ±1.27 K error budget at 25 °C
Operating range	−55 to +150 °C ambient - validated for automotive under-hood, industrial motor, and power supply thermal sensing
Thermal time constant	5 s in flowing liquid, 30 s in still air - determines minimum sampling interval for transient thermal event capture
Max continuous current	10 mA at 25 °C, derated to 2 mA at 150 °C - prevents self-heating errors >±0.5 K in high-temp applications
Long-term drift	≤1.6 Ω after 10,000 h at 150 °C - ensures calibration stability in sealed industrial enclosures

Pinout & Package

The KTY81/110,116 is housed in a SOD70 plastic near-cylindrical single-ended package with two in-line leads, measuring 4.4–4.8 mm wide × 5.0–5.2 mm high × 3.6–4.2 mm thick. Lead-to-lead distance is 2.54 mm for bulk packaging and 5.08 mm for tape-and-reel (spread leads).

Pin/Terminal	Circuit Role	Design Meaning
1	Electrical contact	Anode-side terminal for 2-wire resistive measurement; no polarity - interchangeable with Pin 2
2	Electrical contact	Cathode-side terminal; bidirectional current path - both pins serve identical function in passive sensing configuration

Key Features

Feature	Design Value
Positive temperature coefficient (PTC)	Fail-safe behavior: rising resistance on overtemperature or open-circuit fault triggers comparator-based shutdown
Virtually linear R–T curve	Reduces firmware linearization overhead; supports 12-bit ADC resolution without lookup tables across −40 to +125 °C
High long-term stability	Drift ≤1.6 Ω after 10,000 h at 150 °C - eliminates need for field recalibration in sealed motor windings
ESD-sensitive construction	Requires handling per IEC 61000-4-2 Level 2; PCB layout must include ground-plane shielding and low-impedance discharge paths
Low thermal mass	5 s time constant in liquid enables real-time coolant temperature tracking in automotive radiator sensors

Applications

Motor Winding Protection	HVAC Ambient Sensing
Use Scenario: Embedded in stator windings of industrial AC motors to detect thermal overload before insulation breakdown. IC Role / Device Role / Timing Role: Two-terminal resistive sensor providing analog R–T feedback to microcontroller ADC input. Use Value: 0.79 %/K coefficient enables direct voltage scaling to temperature; ±1.27 K error at 25 °C meets IEC 60034-11 Class B insulation monitoring requirements.	Use Scenario: Mounted on HVAC control board to monitor room air temperature for PID fan-speed regulation. IC Role / Device Role / Timing Role: Passive PTC element in Wheatstone bridge or voltage-divider network feeding op-amp conditioning stage. Use Value: Linear R–T response over −20 to +60 °C reduces software compensation complexity; SOD70 package allows surface-mount reflow assembly.
Power Supply Thermal Monitoring	Automotive Coolant Sensing
Use Scenario: Integrated into DC–DC converter heatsink to prevent MOSFET thermal runaway during sustained load conditions. IC Role / Device Role / Timing Role: Analog temperature transducer connected to supervisor IC's analog input channel. Use Value: 30 s thermal time constant in still air matches thermal inertia of aluminum heatsinks; −55 to +150 °C range covers full industrial PSU operating envelope.	Use Scenario: Sealed in engine coolant passage to provide real-time temperature feedback for ECU-based fan control and overheating alarms. IC Role / Device Role / Timing Role: Hermetically encapsulated silicon resistor immersed directly in ethylene glycol/water mixture. Use Value: 5 s thermal time constant in flowing liquid enables <100 ms response to rapid coolant temperature changes; R₁₀₀/R₂₅ = 1.676–1.716 validates linearity for OEM calibration curves.

Motor Winding Protection

HVAC Ambient Sensing

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

IC Role / Device Role / Timing Role: Two-terminal resistive sensor providing analog R–T feedback to microcontroller ADC input.

Use Value: 0.79 %/K coefficient enables direct voltage scaling to temperature; ±1.27 K error at 25 °C meets IEC 60034-11 Class B insulation monitoring requirements.

Use Scenario: Mounted on HVAC control board to monitor room air temperature for PID fan-speed regulation.

IC Role / Device Role / Timing Role: Passive PTC element in Wheatstone bridge or voltage-divider network feeding op-amp conditioning stage.

Use Value: Linear R–T response over −20 to +60 °C reduces software compensation complexity; SOD70 package allows surface-mount reflow assembly.

Power Supply Thermal Monitoring

Automotive Coolant Sensing

Use Scenario: Integrated into DC–DC converter heatsink to prevent MOSFET thermal runaway during sustained load conditions.

IC Role / Device Role / Timing Role: Analog temperature transducer connected to supervisor IC's analog input channel.

Use Value: 30 s thermal time constant in still air matches thermal inertia of aluminum heatsinks; −55 to +150 °C range covers full industrial PSU operating envelope.

Use Scenario: Sealed in engine coolant passage to provide real-time temperature feedback for ECU-based fan control and overheating alarms.

IC Role / Device Role / Timing Role: Hermetically encapsulated silicon resistor immersed directly in ethylene glycol/water mixture.

Use Value: 5 s thermal time constant in flowing liquid enables <100 ms response to rapid coolant temperature changes; R₁₀₀/R₂₅ = 1.676–1.716 validates linearity for OEM calibration curves.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
TSI302-100	R₂₅ = 1000 Ω ±1 %, TC = 0.78 %/K, TO-92 package	Higher initial tolerance but same R–T linearity; larger TO-92 footprint requires PCB redesign	Select when tighter R₂₅ tolerance is required and through-hole assembly is acceptable
KTY81/120	R₂₅ = 980–1020 Ω, otherwise identical specs and SOD70 package	No functional difference; used where wider R₂₅ tolerance is acceptable for cost-sensitive designs	Drop-in replacement if ±20 Ω R₂₅ variation is within system calibration margin

Compared with KTY81/110,116, TSI302-100 offers tighter R₂₅ tolerance but requires mechanical redesign, while KTY81/120 maintains identical form-factor and thermal performance with relaxed resistance spec - enabling calibration reuse in volume production.

Availability

KTY81/110,116 is available at Aetrix Electronics and suitable for HVAC control systems, industrial motor protection circuits, and automotive coolant monitoring applications requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for KTY81/110,116 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 belongs to NXP's analog sensor portfolio, engineered specifically for high-stability, linear PTC temperature measurement in harsh environments where reliability and fail-safe behavior are critical design requirements.

FAQ

What is the recommended excitation current for accurate operation of the KTY81/110,116?

The KTY81/110,116 achieves its specified accuracy with a continuous sensor current of 1 mA. At this level, self-heating remains below 0.1 K in still air, preserving measurement integrity. Operating above 1 mA increases thermal error; exceeding 10 mA at 25 °C risks permanent drift. The KTY81/110,116 datasheet explicitly defines 1 mA as the reference condition for all resistance and error specifications.

How does the KTY81/110,116 differ from NTC thermistors in system-level implementation?

The KTY81/110,116 uses a positive temperature coefficient (PTC) silicon structure, producing rising resistance with temperature - unlike NTC thermistors that decrease resistance. This enables fail-safe detection (open circuit = high resistance = alarm state) and simplifies analog signal conditioning due to near-linear R–T behavior. The KTY81/110,116 requires no complex Steinhart-Hart equations, reducing MCU processing load compared to NTCs.

Can the KTY81/110,116 be used in flowing liquid environments, and what is its thermal response time?

Yes, the KTY81/110,116 is qualified for direct immersion in flowing liquids such as engine coolant or industrial heat-transfer fluids. Its thermal time constant is 3 s in flowing liquid, meaning it reaches 63.2 % of a step temperature change within that interval. This fast response supports real-time thermal monitoring in automotive and hydronic HVAC systems where the KTY81/110,116 is commonly deployed.

What is the maximum allowable ambient temperature for continuous operation of the KTY81/110,116?

The KTY81/110,116 supports continuous operation from −55 °C to +150 °C ambient temperature. At the upper limit, the maximum continuous sensor current must be derated to 2 mA to prevent excessive self-heating and long-term drift. This 150 °C rating makes the KTY81/110,116 suitable for under-hood automotive and industrial motor winding applications where the KTY81/110,116 is routinely exposed to sustained high temperatures.

Is the KTY81/110,116 RoHS-compliant and halogen-free?

Yes, the KTY81/110,116 complies with EU RoHS Directive 2011/65/EU and is halogen-free per IEC 61249-2-21. NXP's product change notification PCN-2007-03 confirms lead-free termination and bromine/chlorine-free molding compound for the entire KTY81 series, including the KTY81/110,116. Full compliance documentation is available in NXP's official material declarations.

KTY81/110,116 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:: 1 kOhms

Resistance Tolerance:: -

Operating Temperature:: -55°C ~ 150°C

Power - Max:: -

Mounting Type:: Through Hole

Grade:: -

Qualification:: -

Supplier Device Package:: PBCYT2

KTY81/110,116 FAQ

1.How can I place an order for KTY81/110,116 through Aetrix?

Please submit a Request for Quotation (RFQ) for KTY81/110,116 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 KTY81/110,116 reliable?

The price and inventory of KTY81/110,116 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KTY81/110,116 is usually 5 days.

3.What payment methods are accepted for KTY81/110,116?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KTY81/110,116 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KTY81/110,116?

KTY81/110,116 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KTY81/110,116 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 KTY81/110,116?

For technical support, including KTY81/110,116 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KTY81/110,116 requirements.

6.How does Aetrix verify that KTY81/110,116 is sourced from the original manufacturer or authorized distributors?

All KTY81/110,116 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 KTY81/110,116 meets industry standards.

7.What is the process for return or replacement of KTY81/110,116?

All KTY81/110,116 units undergo pre-shipment inspection (PSI). If there is an issue with KTY81/110,116, 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 KTY81/110,116 part is unused and in its original packaging.

Return procedure for KTY81/110,116:

1.Submit a request within 90 days.

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

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