Temperature Sensors - PTC Thermistors

Image Part Number Description / PDF Quantity Rfq
B59873C0120A570

B59873C0120A570

TDK EPCOS

THERMISTOR PTC 45 OHM 20% DISC

0

KTY82/122,215

KTY82/122,215

NXP Semiconductors

THERMISTOR PTC 1.1K OHM TO236AB

0

TFPT0805L5600FM

TFPT0805L5600FM

Vishay / Dale

THERMISTOR PTC 560 OHM 1% 0805

0

B59404B0060A040

B59404B0060A040

TDK EPCOS

THERMISTOR PTC 3.5K OHM 30% RAD

1709

B59100M1155A070

B59100M1155A070

TDK EPCOS

THERMISTOR PTC 100 OHM

8464

B59102R0090A010

B59102R0090A010

TDK EPCOS

THERMISTOR PTC 700 OHM 50% RECT

0

B59100C150A151

B59100C150A151

TDK EPCOS

THERMISTOR PTC 100 OHM

0

TFPT0805L1800JM

TFPT0805L1800JM

Vishay / Dale

THERMISTOR PTC 180 OHM 5% 0805

0

LT7330002A1K5JTE

LT7330002A1K5JTE

TE Connectivity AMP Connectors

THERMISTOR PTC 1.5K OHM 5% 0805

0

PRF21AS471QB5RA

PRF21AS471QB5RA

TOKO / Murata

THERMISTOR PTC 470 OHM 50% 0805

0

KTY21-5

KTY21-5

IR (Infineon Technologies)

THERMISTOR PTC 985 OHM 3% TO92

0

B59102R0270A010

B59102R0270A010

TDK EPCOS

THERMISTOR PTC 1.3K OHM 50% RECT

0

B59339A1502P020

B59339A1502P020

TDK EPCOS

THERMISTOR PTC 1.5K OHM 25% RAD

0

TFPT1206L2700FM

TFPT1206L2700FM

Vishay / Dale

THERMISTOR PTC 270 OHM 1% 1206

0

TFPT0805L4700JM

TFPT0805L4700JM

Vishay / Dale

THERMISTOR PTC 470 OHM 5% 0805

0

TFPT0805L3901JV

TFPT0805L3901JV

Vishay / Dale

THERMISTOR PTC 3.9K OHM 5% 0805

0

B59102R0130A010

B59102R0130A010

TDK EPCOS

THERMISTOR PTC 700 OHM 50% RECT

551

TFPT0603L3900JV

TFPT0603L3900JV

Vishay / Dale

THERMISTOR PTC 390 OHM 5% 0603

0

LT7339002A1K0JTE

LT7339002A1K0JTE

TE Connectivity AMP Connectors

THERMISTOR PTC 1K OHM 5% 0805

0

TFPT0603L1001JV

TFPT0603L1001JV

Vishay / Dale

THERMISTOR PTC 1K OHM 5% 0603

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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