NXP Semiconductors KTY81/210,112

Overview

KTY81/210,112 from NXP Semiconductors is a silicon-based positive temperature coefficient (PTC) temperature sensor in the KTY81 series, designed for precision analog temperature measurement in feedback loops and control systems. At 25 °C, its nominal resistance is 2000 Ω (1980–2020 Ω), with a temperature coefficient of 0.79 %/K and ±1.27 K max error at 25 °C. It operates from −55 °C to +150 °C and is encapsulated in an SOD70 plastic package.

For engineers reviewing the KTY81/210,112 datasheet, KTY81/210,112 pinout, KTY81/210,112 application, or KTY81/210,112 equivalent, this page delivers verified specifications, real-world use cases, pin-level circuit roles, and validated alternative options - all grounded in NXP's official 2008 product data sheet.

Technical Context

The KTY81/210,112 functions as a two-terminal resistive transducer whose resistance increases linearly with ambient temperature. Its PTC behavior provides fail-safe operation: rising resistance under overtemperature conditions enables direct integration into voltage-divider or Wheatstone bridge circuits without active biasing.

It exhibits virtually linear R–T characteristics across −40 °C to +125 °C, with thermal time constants of 30 s in still air, 5 s in still liquid, and 3 s in flowing liquid. The recommended continuous sensing current is 1 mA to minimize self-heating and maintain accuracy within ±1.27 K at 25 °C.

Key Specifications

Pinout & Package

Encapsulated in the SOD70 plastic near-cylindrical single-ended package with two in-line leads, the KTY81/210,112 has no polarity and is symmetrically terminated. Lead-to-lead distance is 2.54 mm for bulk packaging and 5.08 mm for tape-and-reel (spread leads).

Key Features

Applications

Equivalent & Alternatives

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

Compared with KTY81/210,112, KTY81/220 offers lower cost at the expense of tighter accuracy and stability specs, while TSIC506-2000 replaces analog simplicity with digital intelligence - trading passive reliability for programmable flexibility and higher BOM count.

Availability

KTY81/210,112 is available at Aetrix Electronics and suitable for automotive thermal management, industrial process control, and power electronics protection requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for KTY81/210,112 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 as a family of robust, low-cost silicon PTC sensors targeting analog temperature feedback in safety-critical and high-reliability applications where fail-safe behavior and long-term stability are mandatory.

FAQ

What is the nominal resistance of KTY81/210,112 at 25 °C?

The KTY81/210,112 has a nominal resistance of 2000 Ω at 25 °C, with a guaranteed range of 1980 Ω to 2020 Ω per NXP's datasheet. This value serves as the reference point for designing voltage-divider networks and calibrating ADC inputs in temperature measurement circuits using the KTY81/210,112.

Does KTY81/210,112 require external excitation current, and what is the recommended value?

Yes, the KTY81/210,112 requires a constant excitation current to generate a measurable voltage drop. NXP specifies 1 mA as the recommended continuous sensing current (Isen(cont)) to minimize self-heating and maintain accuracy within ±1.27 K at 25 °C. Higher currents increase thermal error and accelerate long-term drift in the KTY81/210,112.

What is the maximum operating temperature for KTY81/210,112, and how does accuracy degrade at extremes?

The KTY81/210,112 is rated for ambient temperatures from −55 °C to +150 °C. Accuracy degrades predictably: maximum temperature error is ±1.27 K at 25 °C, ±3.46 K at 100 °C, and ±14.63 K at 150 °C. These values are derived from resistance tolerance bands and thermal coefficient variation documented in Table 10 of the KTY81/210,112 datasheet.

Is KTY81/210,112 compatible with standard SOD70 footprint layouts?

Yes, the KTY81/210,112 uses the standardized SOD70 package with defined mechanical dimensions: body width 4.4–4.8 mm, height 5.0–5.2 mm, thickness 3.6–4.2 mm, and lead-to-lead distance of 2.54 mm (bulk) or 5.08 mm (tape-and-reel). These match IPC-7351B SOD70 land patterns, ensuring drop-in compatibility in existing PCB designs for the KTY81/210,112.

How does the positive temperature coefficient (PTC) behavior of KTY81/210,112 improve system safety?

The PTC characteristic of the KTY81/210,112 ensures resistance increases monotonically with temperature - enabling inherent fault detection (e.g., open-circuit = infinite resistance = overtemperature alarm) and preventing runaway conditions in analog control loops. Unlike NTC thermistors, the KTY81/210,112 cannot mask failures through decreasing resistance, making it preferred for safety-critical thermal monitoring in the KTY81/210,112 application space.