Infineon Technologies KTY10-5

Overview

KTY10-5 from Infineon Technologies is a silicon-based positive temperature coefficient (PTC) temperature sensor in TO-92 package, with nominal resistance R₂₅ = 1970 Ω ±2% (midpoint of 1950–1990 Ω), operating from −50 °C to +150 °C, and thermal time constant τₐᵢᵣ = 40 s - used for air temperature monitoring in motor winding protection and HVAC control circuits.

For engineers reviewing the KTY10-5 datasheet, KTY10-5 pinout, KTY10-5 application, or KTY10-5 equivalent, this part serves as a polarity-independent, linearized analog temperature sensing element requiring only a 1 mA bias current and offering stable long-term resistance drift performance in industrial thermal management systems.

Technical Context

The KTY10-5 implements a planar n-conducting silicon crystal whose resistance vs. temperature follows a second-order polynomial: R_T = R₂₅ × [1 + α·ΔT + β·(ΔT)²], where α = 7.88×10⁻³ K⁻¹ and β = 1.937×10⁻⁵ K⁻². It delivers a defined temperature factor k_T = R_T/R₂₅, ranging from 0.506 at −50 °C to 2.196 at +150 °C.

No active circuitry or signal conditioning is integrated; it functions as a passive two-terminal resistor whose value changes predictably with ambient temperature. Its symmetrical construction eliminates polarity dependence, and its 40 s air thermal time constant enables stable averaging in slowly varying thermal environments.

Key Specifications

Pinout & Package

TO-92 package with three leads; pins are electrically symmetrical - no designated anode/cathode. Pin 1 and Pin 2 are internally shorted per datasheet drawing; Pin 3 is the third terminal, forming a two-terminal device across any pair of leads.

Key Features

Applications

Equivalent & Alternatives

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

Compared with KTY10-6 and KTY11-5, the KTY10-5 provides the lowest-cost TO-92 option with standard ±2% R₂₅ tolerance and proven long-term stability - ideal for cost-sensitive, non-miniaturized industrial thermal monitoring where 40 s response is sufficient.

Availability

KTY10-5 is available at Aetrix Electronics and suitable for motor protection, HVAC air sensing, automotive cabin control, and power supply thermal monitoring requiring stable component supply across multi-year production cycles.

Supply support for KTY10-5 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

Infineon Technologies is a German semiconductor manufacturer specializing in power management, sensor, and automotive ICs, with leadership in silicon-based temperature sensing and industrial reliability.

The KTY-series was developed specifically for high-stability, wide-range analog temperature measurement in safety-critical thermal protection systems - emphasizing long-term drift performance and mechanical robustness over digital integration.

FAQ

What is the maximum allowable bias current for continuous operation?

The absolute maximum operating current is 5 mA at TA ≤ 25 °C. For continuous operation, 1 mA is recommended to limit self-heating error to less than 0.1 °C. Exceeding 5 mA risks irreversible resistance shift due to localized silicon heating, especially above 85 °C ambient.

Can KTY10-5 be used in liquid immersion applications?

No - the TO-92 package is not rated for liquid immersion. Its epoxy body and lead seal are designed for air/gas environments only. For oil or coolant sensing, use KTY16-6 (screw-thread housing) or KTY19-6M/Z (NPTF or ISO M10 thread), which provide hermetic sealing and mechanical mounting.

How is temperature calculated from measured resistance?

Use the second-order equation: R_T = R₂₅ × [1 + α·ΔT + β·(ΔT)²], with α = 7.88×10⁻³ K⁻¹ and β = 1.937×10⁻⁵ K⁻². Rearranged for temperature: T = [−α + √(α² − 4β(1 − R_T/R₂₅))]/(2β) + 25 °C - valid from −30 °C to +130 °C.

Is there a recommended decoupling capacitor for noise immunity?

Yes - when long supply leads (>10 cm) are used, connect a ≥10 nF ceramic capacitor between the sensor terminals near the PCB entry point. This suppresses induced voltage spikes that could exceed the 25 V absolute maximum rating and cause permanent damage to the silicon element.