Temperature Sensors - PTC Thermistors

Image Part Number Description / PDF Quantity Rfq
TFSW0805-25RF

TFSW0805-25RF

Vishay / Sfernice

TFS W0805 25U 1%

0

TFPT0805L3301JM

TFPT0805L3301JM

Vishay / Dale

THERMISTOR PTC 3.3K OHM 5% 0805

0

TFPT0603L5600FV

TFPT0603L5600FV

Vishay / Dale

THERMISTOR PTC 560 OHM 1% 0603

0

KT110

KT110

IR (Infineon Technologies)

THERMISTOR PTC 1K OHM 3% TO92

0

TFPT0603L6800FV

TFPT0603L6800FV

Vishay / Dale

THERMISTOR PTC 680 OHM 1% 0603

0

B59753C0120A070

B59753C0120A070

TDK EPCOS

THERMISTOR PTC 120 OHM 25% DISC

3919

B59008C0130A040

B59008C0130A040

TDK EPCOS

THERMISTOR PTC 250 OHM RADIAL

2860

TFPT1206L2201FM

TFPT1206L2201FM

Vishay / Dale

THERMISTOR PTC 2.2K OHM 1% 1206

0

TFPT0805L1200JV

TFPT0805L1200JV

Vishay / Dale

THERMISTOR PTC 120 OHM 5% 0805

0

B59249R0155B010

B59249R0155B010

TDK EPCOS

THERMISTOR PTC 3K OHM 35% RECT

0

TFPT1206L4700JV

TFPT1206L4700JV

Vishay / Dale

THERMISTOR PTC 470 OHM 5% 1206

0

TFPT1206L5600JV

TFPT1206L5600JV

Vishay / Dale

THERMISTOR PTC 560 OHM 5% 1206

0

B59100C0140A070

B59100C0140A070

TDK EPCOS

THERMISTOR PTC 100 OHM RADIAL

0

KTY82/110,235

KTY82/110,235

NXP Semiconductors

SILICON TEMPERATURE SENSOR

0

B59100M1060A070

B59100M1060A070

TDK EPCOS

THERMISTOR PTC 100 OHM

285

TFPT0805L6800FM

TFPT0805L6800FM

Vishay / Dale

THERMISTOR PTC 680 OHM 1% 0805

0

TFPTL15L1001FL2T

TFPTL15L1001FL2T

Vishay / Dale

THERMISTOR PTC 1K OHM 1% RADIAL

0

B59810C0160A070

B59810C0160A070

TDK EPCOS

THERMISTOR PTC 1.6 OHM 25% DISC

2

PRF21BD471QB5RA

PRF21BD471QB5RA

TOKO / Murata

THERMISTOR PTC 470 OHM 50% 0805

906

TFPT1206L3300JV

TFPT1206L3300JV

Vishay / Dale

THERMISTOR PTC 330 OHM 5% 1206

0

Temperature Sensors - PTC Thermistors

1. Overview

Positive Temperature Coefficient (PTC) thermistors are resistors with a positive temperature coefficient, meaning their resistance increases significantly with temperature rise. Unlike NTC thermistors, PTC devices exhibit a sharp resistance transition at a critical temperature (Curie point). They are widely used in overtemperature protection, self-regulating heating elements, and temperature sensing applications. Their inherent safety features and reliability make them critical components in modern electronics, automotive systems, and industrial equipment.

2. Main Types and Functional Classification

TypeFunctional CharacteristicsApplication Examples
Ceramic PTC ThermistorsHigh Curie temperature, abrupt resistance change, durableOverheat protection in motors, heaters, and power supplies
Polymer PTC ThermistorsLower switching temperature, resettable fuse functionalityUSB port protection, battery management systems
Switching PTCDigital on/off behavior at threshold temperatureThermal cutoff for appliances, HVAC systems
Linear PTCProportional resistance-temperature responsePrecision temperature measurement in industrial controllers

3. Structure and Composition

PTC thermistors typically consist of polycrystalline ceramic semiconductor materials (e.g., BaTiO3 doped with rare earth elements) with embedded silver or platinum electrodes. The core structure includes: - Semiconductor ceramic body with tailored Curie temperature - Metal electrodes for electrical connection - Protective epoxy or glass coating - Lead wires (axial/radial) or SMD terminations The PTC effect arises from the material's phase transition at Curie temperature, causing resistance spikes due to crystal lattice changes.

4. Key Technical Specifications

ParameterDescriptionImportance
R25 (Resistance at 25 C)Baseline resistance valueDetermines circuit compatibility
Tswitch (Switching Temperature)Critical temperature for resistance jumpApplication-specific threshold setting
Rmin/Rmax RatioResistance range spanIndicates sensitivity and switching capability
Dissipation Factor (mW/ C)Power dissipation per temperature unitAffects thermal response speed
Response Time (ms)Time to reach 90% resistance changeCritical for real-time protection systems

5. Application Fields

Major application sectors include: - Consumer Electronics: Smartphones (battery protection), 3D printers (hotend monitoring) - Automotive: EV battery thermal management, seat heater control - Industrial: Motor overload protection, pipeline freeze detection - Renewable Energy: Solar charge controllers, wind turbine gear monitoring - Medical: Patient warming systems, diagnostic equipment thermal regulation

6. Leading Manufacturers and Products

ManufacturerKey ProductsFeatures
Vishay BeyschlagK2500-FinderAutomotive-grade PTC with 50-150 C range
TE ConnectivityPS224-202UL-certified resettable fuse for power supplies
Murata ElectronicsPXU11S150R0Miniature SMD PTC for IoT devices
EPCOS (TDK)B59904C0150A070High-current PTC for industrial motor protection

7. Selection Guidelines

Key selection criteria: - Required switching temperature vs operating temperature range - Resistance tolerance and stability over lifespan - Package type (through-hole, SMD, bolt-on) - Voltage/current ratings with safety margin - Compliance with standards (UL, RoHS, AEC-Q200 for automotive) - Environmental resistance (humidity, vibration, chemical exposure)

8. Industry Trends

Emerging trends include: - Development of nano-ceramic materials for faster response times (<10ms) - Integration with MEMS technology for IoT sensor nodes - Higher temperature stability beyond 200 C for e-mobility applications - Miniaturization to 0402 SMD package sizes - AI-based predictive thermal management systems using PTC arrays - Increased adoption in hydrogen fuel cell thermal monitoring systems

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