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

NXP Semiconductors KTY83/121,153

Name: KTY83/121,153
Brand: NXP Semiconductors
SKU: KTY83/121,153
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KTY83/121,153

Manufacturer:: NXP Semiconductors

Category:: PTC Thermistors

Package:: DO-204AG, DO-34, Axial

Datasheet:: KTY83/121,153.pdf

Description:: SENSOR PTC 990OHM DO34

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Product details

Overview

KTY83/121 from NXP Semiconductors is a silicon-based positive temperature coefficient (PTC) temperature sensor in a hermetically sealed SOD68 (DO-34) axial-leaded package, delivering 980–1000 Ω resistance at 25 °C, 0.76 %/K temperature coefficient, and ±1.31 K max temperature error at 25 °C for precision thermal monitoring in motor windings and power supply thermal protection circuits.

For engineers reviewing the KTY83/121 datasheet, KTY83/121 pinout, KTY83/121 application, or KTY83/121 equivalent, this page provides verified resistance vs. temperature data, thermal time constants in air/liquid, long-term drift specification (≤1 Ω after 10,000 h at 175 °C), fail-safe PTC behavior, and direct comparison to KTY83/120 and KTY83/122 variants.

Technical Context

The KTY83/121 operates as a two-terminal passive resistive sensor requiring external bias current (typically 1 mA) to generate voltage proportional to temperature. Its PTC response is intrinsically linear over −55 °C to +175 °C, with R₋₅₅/R₂₅ = 0.49–0.51 and R₁₀₀/R₂₅ = 1.65–1.69, enabling direct analog readout without linearization circuitry in many applications.

Thermal response is characterized by τ_th = 20 s in still air, 1 s in still liquid, and 0.5 s in flowing liquid-critical for fast-cycling thermal protection. Maximum continuous sensor current is limited to 2 mA at 175 °C ambient to prevent self-heating-induced measurement error.

Key Specifications

Parameter	Value and Actual Design Meaning
R₂₅	980–1000 Ω at 25 °C with 1 mA bias - defines baseline scaling for analog temperature measurement circuits.
Temperature coefficient	0.76 %/K - enables predictable, monotonic resistance increase per degree, supporting fail-safe overtemperature detection.
R₁₀₀/R₂₅	1.65–1.69 - quantifies resistance ratio at 100 °C vs. 25 °C, used to validate calibration accuracy across industrial range.
Max temp error at 25 °C	±1.31 K - specifies worst-case deviation from true temperature under nominal conditions, critical for closed-loop control stability.
Thermal time constant (liquid)	1 s in still liquid - determines minimum sampling interval for dynamic thermal event capture in coolant or oil immersion.
Long-term drift	≤1 Ω after 10,000 h at 175 °C - guarantees resistance stability in high-reliability automotive and industrial environments.
Ambient range	−55 °C to +175 °C - supports operation in engine bays, power converters, and industrial ovens without derating.

Pinout & Package

Package: SOD68 (DO-34), hermetically sealed glass axial-leaded package with 2 leads, 3.04 mm max diameter, 25.4 mm min lead length.

Pin/Terminal	Circuit Role	Design Meaning
1 (cathode, k)	Current return path	Connected to ground or low-side of bias resistor; polarity must be observed to avoid reverse-bias leakage effects.
2 (anode, a)	Current input terminal	Bias current enters here; voltage measured between pins 1 and 2 yields temperature-proportional signal.

Key Features

Feature	Design Value
Fail-safe PTC behavior	Resistance increases with temperature - ensures open-circuit or high-voltage fault indication on overtemperature, eliminating need for active supervision.
Virtually linear R-T curve	±1.31 K max error at 25 °C and <±7.19 K over full −55 °C to +175 °C range - reduces or eliminates software linearization in microcontroller-based systems.
Long-term stability	Drift ≤1 Ω after 10,000 h at 175 °C - maintains calibration integrity in continuously operating equipment like UPS and motor drives.
Fast thermal response in liquid	τ_th = 0.5 s in flowing liquid - enables real-time thermal shutdown in liquid-cooled inverters and battery packs.
High-temperature capability	Rated to +175 °C ambient - suitable for direct mounting on IGBT heatsinks and transformer windings without external thermal isolation.

Applications

Motor Winding Protection	Power Supply Thermal Monitoring
Use Scenario: Embedded in stator windings of industrial AC motors to detect overheating before insulation failure. IC Role / Device Role / Timing Role: Passive resistive temperature sensing element interfaced to comparator or ADC input. Use Value: 0.76 %/K PTC slope provides >75 Ω/°C change near 100 °C, enabling reliable detection of 5 °C rise with standard 12-bit ADC resolution.	Use Scenario: Mounted on primary-side MOSFET heatsink in telecom rectifiers to throttle output during thermal overload. IC Role / Device Role / Timing Role: Analog temperature transducer feeding into dedicated thermal management IC or microcontroller ADC. Use Value: ±1.31 K accuracy at 25 °C and <±4.73 K at 130 °C ensures precise margining against thermal shutdown thresholds in high-efficiency SMPS.
Automotive Cabin Heater Control	Industrial Oven Temperature Feedback
Use Scenario: Integrated into HVAC blend door actuator housing to regulate cabin air temperature in passenger vehicles. IC Role / Device Role / Timing Role: Two-wire analog temperature sensor providing feedback to HVAC controller MCU. Use Value: R₋₄₀/R₂₅ = 0.556–0.586 and R₈₅/R₂₅ = 1.430–1.485 enable single-point calibration across full automotive ambient range (−40 °C to +85 °C).	Use Scenario: Directly embedded in heating element assembly of food processing ovens for closed-loop PID temperature control. IC Role / Device Role / Timing Role: High-stability resistive sensor connected to industrial PLC analog input module. Use Value: 175 °C max ambient rating and ≤1 Ω drift after 10,000 h allow continuous operation without recalibration in Class H insulation environments.

Motor Winding Protection

Power Supply Thermal Monitoring

Use Scenario: Embedded in stator windings of industrial AC motors to detect overheating before insulation failure.

IC Role / Device Role / Timing Role: Passive resistive temperature sensing element interfaced to comparator or ADC input.

Use Value: 0.76 %/K PTC slope provides >75 Ω/°C change near 100 °C, enabling reliable detection of 5 °C rise with standard 12-bit ADC resolution.

Use Scenario: Mounted on primary-side MOSFET heatsink in telecom rectifiers to throttle output during thermal overload.

IC Role / Device Role / Timing Role: Analog temperature transducer feeding into dedicated thermal management IC or microcontroller ADC.

Use Value: ±1.31 K accuracy at 25 °C and <±4.73 K at 130 °C ensures precise margining against thermal shutdown thresholds in high-efficiency SMPS.

Automotive Cabin Heater Control

Industrial Oven Temperature Feedback

Use Scenario: Integrated into HVAC blend door actuator housing to regulate cabin air temperature in passenger vehicles.

IC Role / Device Role / Timing Role: Two-wire analog temperature sensor providing feedback to HVAC controller MCU.

Use Value: R₋₄₀/R₂₅ = 0.556–0.586 and R₈₅/R₂₅ = 1.430–1.485 enable single-point calibration across full automotive ambient range (−40 °C to +85 °C).

Use Scenario: Directly embedded in heating element assembly of food processing ovens for closed-loop PID temperature control.

IC Role / Device Role / Timing Role: High-stability resistive sensor connected to industrial PLC analog input module.

Use Value: 175 °C max ambient rating and ≤1 Ω drift after 10,000 h allow continuous operation without recalibration in Class H insulation environments.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
KTY83/120	R₂₅ = 980–1020 Ω; ±2.62 K max error at 25 °C; higher R₁₀₀/R₂₅ spread (1.65–1.69 vs. 1.65–1.69 same range but wider tolerance band)	Suitable where wider initial resistance tolerance is acceptable, e.g., non-critical ambient monitoring.	Select KTY83/120 only if system-level calibration accommodates ±2.62 K baseline error; KTY83/121 offers tighter 25 °C accuracy.
KTY83/122	R₂₅ = 1000–1020 Ω; identical ±1.31 K error at 25 °C; R₁₀₀/R₂₅ = 1.65–1.69 same spec, but 1000 Ω nominal enables higher signal voltage at same bias current.	Preferred when higher baseline voltage output improves SNR in noisy industrial environments.	Choose KTY83/122 for improved ADC resolution margin; KTY83/121 remains optimal for legacy designs calibrated to 990 Ω nominal.

Compared with KTY83/120 and KTY83/122, the KTY83/121 delivers the tightest R₂₅ tolerance (980–1000 Ω) among the /12x series while maintaining identical thermal performance and long-term stability-making it the preferred choice for applications requiring minimal factory calibration effort and consistent thermal trip points.

Availability

KTY83/121 is available at Aetrix Electronics and suitable for motor winding protection, power supply thermal monitoring, and industrial oven temperature feedback requiring stable component supply across extended temperature ranges and long service life.

Supply support for KTY83/121 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 KTY83 series belongs to NXP's analog sensor product line, designed specifically for high-reliability, wide-temperature-range thermal sensing in safety-critical and maintenance-free systems where long-term drift and fail-safe behavior are mandatory.

FAQ

What is the maximum continuous operating current for KTY83/121 at 175 °C ambient?

The KTY83/121 supports a maximum continuous sensor current of 2 mA at 175 °C ambient temperature, as defined in Table 5 of the NXP datasheet. Exceeding this limit risks self-heating errors and accelerated long-term drift. At 25 °C, the limit rises to 10 mA, but 1 mA is recommended for precision measurement to minimize thermal loading. This current rating directly governs the design of the bias resistor network used with KTY83/121.

How does the resistance vs. temperature behavior of KTY83/121 differ from thermistors or RTDs?

Unlike NTC thermistors (which decrease resistance with temperature) or platinum RTDs (which offer near-linear resistance increase but require complex excitation), the KTY83/121 exhibits a predictable, monotonic PTC response with 0.76 %/K coefficient and R₁₀₀/R₂₅ = 1.65–1.69. Its silicon construction provides better long-term stability than NTCs and lower cost than RTDs, while its simple two-terminal interface avoids the 3-/4-wire complexity of RTDs. This makes KTY83/121 ideal for cost-sensitive, high-reliability analog thermal sensing where KTY83/121 replaces more complex solutions.

Can KTY83/121 be used in flowing liquid environments, and what is its thermal response time?

Yes, the KTY83/121 is rated for use in flowing liquid environments, with a specified thermal time constant (τ_th) of 0.5 seconds-defined as the time required to reach 63.2 % of the total temperature difference. This rapid response enables real-time thermal monitoring in liquid-cooled battery packs, hydraulic systems, and heat exchangers. The SOD68 glass package ensures hermetic sealing and chemical resistance, making KTY83/121 suitable for direct immersion where electrical isolation and corrosion resistance are required.

What is the long-term resistance drift specification for KTY83/121, and under what conditions is it measured?

The KTY83/121 exhibits a maximum resistance drift of ≤1 Ω after 10,000 hours of continuous operation at 175 °C ambient temperature, as specified in Table 6 of the NXP datasheet. This drift value is measured at 25 °C after thermal stabilization and reflects the device's intrinsic material stability-not including solder joint or PCB stress effects. This specification confirms KTY83/121's suitability for mission-critical applications such as industrial motor protection and aerospace power systems where recalibration is impractical.

Is KTY83/121 pin-compatible with other KTY83 series variants like KTY83/110 or KTY83/151?

Yes, all KTY83 series devices-including KTY83/121, KTY83/110, and KTY83/151-share identical SOD68 (DO-34) packaging and 2-pin axial-leaded configuration with cathode (pin 1) and anode (pin 2) assignments. However, their resistance values and temperature error profiles differ significantly: KTY83/110 has R₂₅ = 990–1010 Ω and ±3.08 K error at −55 °C, while KTY83/151 has R₂₅ = 950–1000 Ω and ±4.92 K error at −55 °C. Therefore, KTY83/121 is mechanically interchangeable but requires circuit recalibration due to distinct R-T characteristics.

KTY83/121,153 Specifications

Product attributes: Attribute value

Manufacturer:: NXP Semiconductors

Series:: KTY83

Package/Case:: DO-204AG, DO-34, Axial

Packaging:: Bulk

Product Status:: Obsolete

Resistance @ 25°C:: 990 Ohms

Resistance Tolerance:: -

Operating Temperature:: -55°C ~ 175°C

Power - Max:: -

Mounting Type:: Through Hole

Grade:: -

Qualification:: -

Supplier Device Package:: DO-34

KTY83/121,153 FAQ

1.How can I place an order for KTY83/121,153 through Aetrix?

Please submit a Request for Quotation (RFQ) for KTY83/121,153 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 KTY83/121,153 reliable?

The price and inventory of KTY83/121,153 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KTY83/121,153 is usually 5 days.

3.What payment methods are accepted for KTY83/121,153?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KTY83/121,153 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KTY83/121,153?

KTY83/121,153 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KTY83/121,153 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 KTY83/121,153?

For technical support, including KTY83/121,153 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KTY83/121,153 requirements.

6.How does Aetrix verify that KTY83/121,153 is sourced from the original manufacturer or authorized distributors?

All KTY83/121,153 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 KTY83/121,153 meets industry standards.

7.What is the process for return or replacement of KTY83/121,153?

All KTY83/121,153 units undergo pre-shipment inspection (PSI). If there is an issue with KTY83/121,153, 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 KTY83/121,153 part is unused and in its original packaging.

Return procedure for KTY83/121,153:

1.Submit a request within 90 days.

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

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