Low Rho SMD Series - PolySwitch packaged PPTC for general electronics overcurrent protection

Low Rho SMD
Roll Over to Zoom
Disclaimer Notice

Information furnished is believed to be accurate and reliable. However, users should independently evaluate the suitability of and test each product selected for their own applications. Littelfuse products are not designed for, and shall not be used for, any purpose (including, without limitation, military, aerospace, medical, life-saving, life-sustaining or nuclear facility applications, devices intended for surgical implant into the body, or any other application in which the failure or lack of desired operation of the product may result in personal injury, death, or property damage) other than those expressly set forth in applicable Littelfuse product documentation. Warranties granted by Littelfuse shall be deemed void for products used for any purpose not expressly set forth in applicable Littelfuse documentation. Littelfuse shall not be liable for any claims or damages arising out of products used in applications not expressly intended by Littelfuse as set forth in applicable Littelfuse documentation. The sale and use of Littelfuse products is subject to Littelfuse Terms and Conditions of Sale, unless otherwise agreed by Littelfuse. "Littelfuse" includes Littelfuse, Inc., and all of its affiliate entities.

PolySwitch® low resistivity SMD (surface-mount device) is versatile device well suited for general applications which have space-constrained, low power dissipation and high environmental reliability requirements.

The devices can help provide both overcurrent and overtemperature protection for battery pack PCMs (protection circuit modules), circuit PCBA and signal/power I/O interface. The resettable feature ensures the device will “Trip” and protect the application during the faults and yet regain the functions once the error is removed.

The low resistivity SMD series comprises 20 devices. In the model number descriptions, the “micro” prefix refers to the 1210 form factor and the “nano” prefix refers to the 1206 form factor.


  • Current ratings from 1.75 to 6.0A
  • Maximum electrical rating: Voltage 6VDC and short circuit current 50A
  • RoHS compliant
  • Halogen free (refers to: Br<=900ppm, Cl<=900ppm, Br+Cl<=1500ppm)
  • Agency recognition: UL, CSA, TÜV


  • Exclusive and robust “Packaged-Chip” design to withstand thermal soldering and stressed molding process
  • Available in compact 1206 and 1210 sizes to accommodate industrial standard footprint and save the board space
  • Ultra-low internal resistance Reset automatically
  • Fast time-to -trip


  • Mobile and smart phones
  • Wearable devices
  • Portable game console
  • VR/AR head mount display (HMD)
  • Tablets and eBook
  • Portable printed and projector
  • Li-ion battery Powered Mobile Devices
  • USB Connection Ports

Access specifications, certifications, check availability and order parts below

Catalog #IHold (A)ITRIP
Max Volts
Trip Time
Max Operating Temp (°C)Packaging
microSMD190LR-21.94.965010.0060.0219.5412106Tape & ReelProduct SpecificationCheckOrder
microSMD200LR-22565010.0060.0219.5412106Tape & ReelProduct SpecificationCheckOrder
microSMD250LR-A-22.55.265010.0050.0189.5512106Tape & ReelProduct SpecificationCheckOrder
microSMD350LR-23.5965010.00250.011101210685Tape & ReelProduct SpecificationCheck
microSMD350LR-D-23.5965010.00250.0119.51012106Tape & ReelProduct SpecificationCheckOrder
microSMD380LR-23.8965010.00250.0099.51012106Tape & ReelProduct SpecificationCheckOrder
microSMD400LR-24965010.00250.0099.51012106Tape & ReelProduct SpecificationCheckOrder
microSMD450LR-24.5955010.00250.0119.51012105Tape & ReelProduct SpecificationCheckOrder
microSMD500LR-251065010.0020.00725212106Tape & ReelProduct SpecificationCheckOrder
microSMD550LR-25.51155010.0020.00625212105Tape & ReelProduct SpecificationCheckOrder
microSMD600LR-261265010.0020.00625212106Tape & ReelProduct SpecificationCheckOrder
nanoSMD175LR-21.75565010.0080.0349.5112066Tape & ReelProduct SpecificationCheckOrder
nanoSMD200LR-22665010.0060.0249.5312066Tape & ReelProduct SpecificationCheckOrder
nanoSMD270LR-22.76.365010.0050.0188512066Tape & ReelProduct SpecificationCheckOrder
nanoSMD350LR-23.56.365010.0040.0188512066Tape & ReelProduct SpecificationCheckOrder
nanoSMD380LR-23.8865010.0040.0149.51012066Tape & ReelProduct SpecificationCheckOrder
nanoSMD400LR-24865010.0040.0120212066Tape & ReelProduct SpecificationCheckOrder
nanoSMD450LR-24.5965010.0020.00825212066Tape & ReelProduct SpecificationCheckOrder
nanoSMD500LR-251065010.0020.00821206685Tape & ReelProduct SpecificationCheck
nanoSMD500LR-D-251065010.0020.00825212066Tape & ReelProduct SpecificationCheckOrder
nanoSMD550LR-25.51165010.0020.007525212066Tape & ReelProduct SpecificationCheckOrder
nanoSMD600LR-261265010.0020.00725212066Tape & ReelProduct SpecificationCheckOrder