The B57891M222J is a positive temperature coefficient (PTC) thermistor manufactured by EPCOS (TDK). PTC thermistors are ceramic semiconductor resistors with a positive temperature coefficient, meaning their resistance increases as their temperature increases. This property makes them useful for a variety of applications, including overcurrent protection and self-regulating heating.

Applications

• Overcurrent protection: Used to protect circuits from excessive current flow, acting as a resettable fuse.
• Self-regulating heaters: Employed in applications where a constant temperature needs to be maintained, such as in automotive applications (e.g., diesel pre-heating).
• Motor starting: Used to provide a starting boost to motors and then reduce current after startup.
• Short-circuit protection: Provides protection against short circuits in various electronic devices.
• Demagnetization circuits: Found in CRT displays for demagnetizing the screen.

Features

• Positive temperature coefficient: Resistance increases significantly with temperature.
• Self-resetting: Automatically resets after the overcurrent condition is removed.
• Compact size: Small footprint allows for easy integration into various circuits.
• High reliability: Robust construction ensures long-term performance.
• Lead-free terminations: Compliant with environmental regulations.

Benefits

• Effective overcurrent protection: Protects circuits from damage due to excessive current.
• Automatic reset: Eliminates the need for manual replacement after an overcurrent event.
• Simplified circuit design: Reduces the complexity of protection circuits.
• Improved safety: Prevents overheating and potential fire hazards.
• Cost-effective solution: Provides a reliable and affordable protection mechanism.

Additional Details

The specific characteristics of the B57891M222J, such as its resistance at a specific temperature, switching temperature, and maximum current, can be found in the product datasheet provided by EPCOS (TDK). These thermistors are typically made from doped barium titanate ceramic materials and are available in various leaded and surface mount packages. The construction ensures a fast response time to temperature changes and reliable operation over a wide range of environmental conditions. Always refer to the datasheet for detailed electrical and thermal specifications to ensure proper application.