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NXP Semiconductors KTY81/122,112
- Part No.:
- KTY81/122,112
- Manufacturer:
- NXP Semiconductors
- Category:
- PTC Thermistors
- Package:
- TO-226-2, TO-92-2 (TO-226AC)
- Datasheet:
-
KTY81/122,112.pdf
- Description:
- SENSOR PTC 1.01KOHM PBCYT2
- Quantity:
- Payment:
- Shipping:
Inventory:4,870
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Product details
Overview
KTY81/122,112 from NXP Semiconductors is a silicon-based positive temperature coefficient (PTC) temperature sensor in SOD70 plastic package, with nominal resistance of 1000 Ω at 25 °C, ±1.27 K max temperature error at 25 °C, and 0.79 %/K temperature coefficient - used for precision thermal monitoring in HVAC control circuits, motor winding protection, and power supply thermal regulation.
For engineers reviewing the KTY81/122,112 datasheet, KTY81/122,112 pinout, KTY81/122,112 application, or KTY81/122,112 equivalent, this page delivers verified electrical specs, validated SOD70 package mapping, confirmed two-terminal passive operation, and real-world use cases aligned to industrial temperature sensing requirements.
Technical Context
The KTY81/122,112 operates as a two-terminal resistive element whose resistance increases linearly with ambient temperature across −55 °C to +150 °C. Its PTC behavior provides fail-safe thermal feedback in overtemperature detection circuits without external biasing circuitry.
Resistance is specified at 1 mA continuous sensor current (Isen(cont)), with thermal time constants of 30 s in still air, 5 s in still liquid, and 3 s in flowing liquid - enabling rapid response in liquid-cooled systems and stable drift performance (≤1.6 Ω resistance shift after 10,000 h at 150 °C).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| R25 | 1000 Ω (nominal resistance at 25 °C; defines baseline calibration point) |
| TC | 0.79 %/K (linear PTC slope; enables predictable resistance vs. temperature interpolation) |
| R100/R25 | 1.696 (resistance ratio at 100 °C vs. 25 °C; confirms usable range up to 100 °C) |
| ∆R25 drift | ≤1.6 Ω after 10,000 h at 150 °C (supports long-term reliability in high-temp environments) |
| τth (liquid) | 5 s (thermal time constant in still liquid; suitable for coolant or oil temperature monitoring) |
| Tamb range | −55 °C to +150 °C (enables operation in automotive under-hood and industrial motor applications) |
| Isen(cont) | 1 mA recommended (ensures low self-heating and ≤±1.27 K error at 25 °C) |
Pinout & Package
Encapsulated in SOD70 plastic near-cylindrical single-ended package with two in-line leads; lead-to-lead distance is 2.54 mm for bulk packaging and 5.08 mm for tape-and-reel (spread leads). Body dimensions: 4.4–4.8 mm width × 5.0–5.2 mm height × 3.6–4.2 mm thickness.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Electrical contact | Non-polarized terminal; interchangeable with Pin 2 in 2-wire resistance measurement |
| 2 | Electrical contact | Non-polarized terminal; completes 2-terminal resistive path; no internal polarity or directionality |
Key Features
| Feature | Design Value |
|---|---|
| Positive temperature coefficient | Fail-safe behavior: resistance rises with temperature, simplifying overtemp detection logic |
| Virtually linear R-T curve | Enables accurate temperature estimation using simple polynomial or lookup-table interpolation |
| Long-term stability | Drift ≤1.6 Ω after 10,000 h at 150 °C supports 10+ year deployments in sealed systems |
| ESD-sensitive construction | Requires handling per IEC 61000-4-2 Level 2; avoids field failures due to static discharge damage |
| SOD70 mechanical robustness | Plastic encapsulation withstands vibration, humidity, and thermal cycling per AEC-Q200 Class 1 |
Applications
| Motor Winding Protection | Power Supply Thermal Regulation |
|---|---|
Use Scenario: Embedded in stator windings of industrial AC motors to detect overheating during overload or cooling failure. IC Role / Device Role / Timing Role: Passive resistive sensor providing analog R-T feedback to microcontroller ADC input. Use Value: Enables early shutdown before insulation breakdown; leverages 150 °C max rating and 5 s liquid τth for fast response in oil-cooled motors. | Use Scenario: Mounted on heatsink near DC-DC converter MOSFETs to monitor thermal derating thresholds. IC Role / Device Role / Timing Role: Two-terminal analog temperature transducer interfaced via constant-current source and precision ADC. Use Value: Supports dynamic frequency scaling and current limiting at 100 °C; uses R100/R25 = 1.696 for calibrated trip-point accuracy. |
| HVAC Air Duct Sensing | Automotive Cabin Temperature Control |
Use Scenario: Installed in HVAC ductwork to measure supply air temperature for PID-controlled blower speed and valve positioning. IC Role / Device Role / Timing Role: Ambient temperature sensing element with direct 1 mA excitation and ratiometric ADC conversion. Use Value: Delivers ±1.27 K error at 25 °C and <±3.5 K error across 0–50 °C range, meeting ASHRAE Class II accuracy requirements. | Use Scenario: Integrated into automotive cabin air intake module to provide feedback for automatic climate control system. IC Role / Device Role / Timing Role: Passive PTC thermistor mounted on PCB with conformal coating for humidity resistance. Use Value: Operates reliably from −40 °C to +85 °C ambient; utilizes SOD70 package for compact mounting and ESD-hardened handling per ISO 10605. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar temperature sensing applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| KTY81/121 | R25 = 980–1000 Ω (lower nominal resistance); identical TC, package, and R-T curve shape | Slightly lower baseline resistance requires recalibration but same thermal response and stability | Select when tighter low-end resistance tolerance (±20 Ω) is required over nominal 1000 Ω |
| NTCG164BF103FT1 | NTC ceramic thermistor (negative TC); R25 = 10 kΩ; B25/85 = 3950 K; different R-T nonlinearity | Requires different signal conditioning and lookup tables; not drop-in compatible | Choose only if NTC behavior is preferred for higher sensitivity below 25 °C or legacy NTC interface compatibility |
Compared with KTY81/122,112, KTY81/121 offers marginally lower R25 with identical stability and package, while NTCG164BF103FT1 introduces fundamentally different NTC behavior requiring full signal chain redesign - making KTY81/122,112 optimal for new PTC-based linear thermal monitoring systems.
Availability
KTY81/122,112 is available at Aetrix Electronics and suitable for HVAC control systems, motor protection circuits, and power supply thermal management requiring stable component supply, traceable lot history, and long-lifecycle support.
Supply support for KTY81/122,112 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 markets.
The KTY81 series is part of NXP's analog sensor portfolio, designed specifically for high-stability, linear PTC temperature measurement in harsh environments where reliability and long-term drift performance are critical.
FAQ
What is the nominal resistance of KTY81/122,112 at 25 °C?
The KTY81/122,112 has a nominal resistance of 1000 Ω at 25 °C, with a guaranteed range of 1000 Ω to 1020 Ω under 1 mA test current. This value serves as the primary calibration reference for resistance-to-temperature conversion in the KTY81/122,112 design, and is directly traceable to Table 1 and Table 6 in the NXP datasheet Rev. 05.
Does KTY81/122,112 require external biasing or signal conditioning?
No, the KTY81/122,112 is a passive two-terminal device requiring only a stable 1 mA current source for excitation. It does not integrate amplification, ADC, or digital interface - all signal conditioning must be implemented externally. The KTY81/122,112 relies on its inherent PTC linearity and low drift to simplify front-end design while maintaining accuracy.
What is the maximum operating temperature for KTY81/122,112?
The KTY81/122,112 is rated for continuous operation from −55 °C to +150 °C ambient temperature. At +150 °C, the maximum continuous sensor current is reduced to 2 mA to limit self-heating, and long-term drift remains within 1.6 Ω after 10,000 hours - confirming suitability for under-hood automotive and industrial motor winding applications.
How does the thermal time constant of KTY81/122,112 affect system response?
The KTY81/122,112 exhibits a thermal time constant (τth) of 30 s in still air, 5 s in still liquid, and 3 s in flowing liquid. This means it reaches 63.2% of a step temperature change within those durations - making it responsive enough for coolant or oil temperature monitoring (5 s), but too slow for rapid transient air temperature capture without airflow enhancement.
Is KTY81/122,112 pin-compatible with other KTY81 series variants?
Yes, all KTY81 series devices including KTY81/122,112 share identical SOD70 package, two-terminal pinout, and mechanical footprint. Substituting KTY81/121 or KTY81/120 requires only recalibration due to differing R25 values (980–1000 Ω vs. 1000–1020 Ω), with no PCB layout changes needed for the KTY81/122,112 replacement.
KTY81/122,112 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- KTY81
- Package/Case:
- TO-226-2, TO-92-2 (TO-226AC)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Resistance @ 25°C:
- 1.01 kOhms
- Resistance Tolerance:
- -
- Operating Temperature:
- -55°C ~ 150°C
- Power - Max:
- -
- Mounting Type:
- Through Hole
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- PBCYT2
KTY81/122,112 FAQ
1.How can I place an order for KTY81/122,112 through Aetrix?
Please submit a Request for Quotation (RFQ) for KTY81/122,112 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 KTY81/122,112 reliable?
The price and inventory of KTY81/122,112 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KTY81/122,112 is usually 5 days.
3.What payment methods are accepted for KTY81/122,112?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KTY81/122,112 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for KTY81/122,112?
KTY81/122,112 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your KTY81/122,112 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 KTY81/122,112?
For technical support, including KTY81/122,112 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KTY81/122,112 requirements.
6.How does Aetrix verify that KTY81/122,112 is sourced from the original manufacturer or authorized distributors?
All KTY81/122,112 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 KTY81/122,112 meets industry standards.
7.What is the process for return or replacement of KTY81/122,112?
All KTY81/122,112 units undergo pre-shipment inspection (PSI). If there is an issue with KTY81/122,112, 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 KTY81/122,112 part is unused and in its original packaging.
Return procedure for KTY81/122,112:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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