MICROSMD450LR-C-2 Littelfuse PTC RESET FUSE 12V 4.5A 1206


The "MICROSMD450LR-C-2" is a specific PTC (Positive Temperature Coefficient) resettable fuse produced by Littelfuse. Here's a breakdown of the part number and an overview of the fuse's specifications.


Part Number Breakdown:

  • MICROSMD450LR: This is the basic part number, indicating the series name or product family designation by Littelfuse.
  • C-2: This alphanumeric code, "C-2", often represents specific variants, packaging, or revisions of the product.

Overview of Specifications:

  • Type: PTC Resettable Fuse - PTC resettable fuses are often used as overcurrent protection devices.
  • Rated Voltage: 12V - This indicates the maximum voltage the fuse can handle.
  • Rated Current: 4.5A - This is the current at which the fuse will trip and limit the flow of current.
  • Package Size: 1206 - This refers to the physical dimensions of the fuse.

Common Applications:

Resettable fuses with these specifications are typically used in various electronic and electrical applications, including:

  • Overcurrent Protection: Resettable fuses serve as protection devices against overcurrent situations in electronic circuits.
  • Power Management: Used in power distribution systems to protect against overloads and short circuits.
  • Electronics Protection: Found in consumer electronics, industrial controls, and automotive applications to prevent damage from excessive currents.


Littelfuse is a well-known manufacturer of circuit protection devices and solutions, including fuses, PTC resettable fuses, thyristors, varistors, and other related products.

Additional Considerations:

When integrating this PTC resettable fuse into a circuit, it's important to ensure that the maximum voltage and current ratings of the fuse are suitable for the application. Additionally, check the time-current characteristics to verify the fuse's response time under various overcurrent conditions. Lastly, consider the time required for the fuse to reset once the fault condition is addressed, as this can affect overall system performance. Always follow manufacturer guidelines and datasheets for proper usage and installation.