NXP Semiconductors KTY81/150,112

Overview

KTY81/150,112 from NXP Semiconductors is a silicon-based positive temperature coefficient (PTC) temperature sensor in SOD70 plastic package, designed for precision analog temperature measurement in industrial control and automotive thermal monitoring systems. It delivers 950–1050 Ω resistance at 25 °C, 0.79 %/K temperature coefficient, ±6.35 K max error at 25 °C, and operates from −55 °C to +150 °C.

For engineers reviewing the KTY81/150,112 datasheet, KTY81/150,112 pinout, KTY81/150,112 application, or KTY81/150,112 equivalent, this page provides verified specifications, package geometry, real-world use cases, and validated alternative parts for thermal sensing circuits requiring stable PTC response and long-term drift <1.6 Ω over 10,000 h at 150 °C.

Technical Context

The KTY81/150,112 uses monocrystalline silicon resistive sensing element with intrinsic PTC behavior-resistance increases predictably with temperature, enabling direct analog voltage-to-temperature conversion via simple current-source biasing. Its near-linear R-T curve (R₁₀₀/R₂₅ = 1.676–1.716) supports accurate interpolation without complex polynomial compensation.

Designed for continuous operation at ≤10 mA (free air, 25 °C) or ≤2 mA (150 °C), it features fail-safe behavior: open-circuit or short-circuit faults produce out-of-range resistance values detectable by ADC monitoring. Thermal time constant is 30 s in still air and 3 s in flowing liquid-enabling responsive thermal feedback in coolant or HVAC loop applications.

Key Specifications

Pinout & Package

The KTY81/150,112 is housed in the SOD70 plastic near-cylindrical single-ended package with two in-line leads. Dimensions: 4.4–4.8 mm body width, 5.0–5.2 mm height, 3.6–4.2 mm thickness, 2.54 mm lead pitch (bulk) or 5.08 mm (reel, spread leads).

Key Features

Applications

Equivalent & Alternatives

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

Compared with KTY81/120 and NTCG104EF104FT1X, the KTY81/150,112 offers superior high-temperature capability (150 °C), inherent linearity for simplified firmware, and fail-safe PTC response-making it optimal for industrial and automotive thermal protection where reliability above 125 °C is mandatory.

Availability

KTY81/150,112 is available at Aetrix Electronics and suitable for motor winding monitoring, automotive HVAC control, industrial oven feedback, and power supply thermal protection requiring stable component supply across extended temperature ranges and long service life.

Supply support for KTY81/150,112 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 was developed by NXP specifically for robust, low-cost analog temperature sensing in harsh environments-emphasizing long-term stability, PTC safety, and compatibility with standard PCB assembly processes.

FAQ

What is the maximum continuous operating current for KTY81/150,112 at 150 °C?

The KTY81/150,112 supports a maximum continuous sensor current of 2 mA at 150 °C in free air, as specified in Table 5 of the NXP datasheet. Exceeding this value risks self-heating-induced measurement error or accelerated long-term drift. At 25 °C, the limit rises to 10 mA-allowing higher signal-to-noise ratio in cooler environments. Always verify thermal dissipation in your PCB layout using the device's 30 s air thermal time constant.

How does the resistance tolerance of KTY81/150,112 affect temperature measurement accuracy?

KTY81/150,112 has a resistance tolerance of ±100 Ω at 25 °C (950–1050 Ω), translating to ±6.35 K maximum temperature error at that point per Table 9. This initial tolerance dominates low-end accuracy; however, its excellent long-term stability (≤1.6 Ω drift over 10,000 h at 150 °C) ensures minimal calibration drift in deployed systems. For highest accuracy, perform 2-point calibration at 0 °C and 100 °C using the published R₁₀₀/R₂₅ ratio.

Can KTY81/150,112 be used in flowing liquid environments, and what is its thermal response time?

Yes, KTY81/150,112 is rated for use in flowing liquid with a thermal time constant of 3 seconds-the time required to reach 63.2% of the final temperature delta. This makes it suitable for real-time coolant temperature monitoring in automotive radiators or industrial heat exchangers. Ensure mechanical mounting avoids flow-induced vibration and conforms to the SOD70 package's 14.5 mm max length and 5.2 mm height envelope.

Is KTY81/150,112 polarity-sensitive, and how should it be connected in circuit?

No, KTY81/150,112 is a passive, symmetric, non-polarized resistive element-Pins 1 and 2 are electrically identical. It must be biased with a constant current (typically 1 mA) to generate a measurable voltage proportional to temperature. No orientation or polarity marking is required during placement; either lead may connect to the current source or ground reference.

What packaging options are available for KTY81/150,112, and how do they affect assembly?

KTY81/150,112 is supplied in bulk (2.54 mm lead pitch) or tape-and-reel (5.08 mm spread leads). Bulk packaging suits manual or semi-automated insertion; tape-and-reel enables high-speed pick-and-place with standardized 12.7 mm pitch and 4 mm feed hole diameter. Both versions share identical SOD70 mechanical dimensions and thermal specs-only lead configuration differs for assembly compatibility.