Skip to content
mbedded.ninja

SOT-227 Component Package

Authors:
Geoffrey Hunter
Geoffrey Hunter
Published On:
Apr 2, 2026
Last Updated:
Apr 2, 2026

SOT-227 is a high-power package with M4 screw terminals. It is used by companies such as Vishay and IXYS for diodes (an example rating is a 1200V, 140A diode). In many cases, all four electrical terminals are isolated from the backside (which is designed to be bonded to a heatsink).

A photo of the SOT-227 component package.1

Synonyms

  • ISOTOP: Microsemi’s package name.2
  • SOT-227-4, miniBLOC: DigiKey’s package name.
  • minibloc: IXYS’s package name.3
  • SOT-227B: Package name used by IXYS and Littelfuse (the B might be referring to either “backside”, “bonded” or perhaps the second revision of the package, just like Vishay’s “Generation 2” dimensions).3 4

Dimensions

The dimensions of the Vishay SOT-227 component package are shown in This is a placeholder for the reference: fig-sot-227-vishay-gen-2-dimensions. Note these are specified as the “Generation 2” dimensions (I’m not sure what Generation 1 dimensions are).

The dimensions of the SOT-227 component package from Vishay.5

Thermal Resistance

To pick on a specific example in the SOT-227 package, the Vishay VS-HFA140FA120 HEXFRED 140A ultrafast soft recovery diode has a junction-to-case thermal resistance of RθJC=0.35∘C/WR_{\theta JC} = 0.35^{\circ}C/W (max.) when one of the legs is conducting, and RθJC=0.175∘C/WR_{\theta JC} = 0.175^{\circ}C/W (max.) when both legs are conducting. It has a very low case-to-heatsink thermal resistance of RθCS=0.05∘C/WR_{\theta CS} = 0.05^{\circ}C/W (typ.).6

Microsemi’s application note Mounting Considerations for the SOT-227 Package provides some in-depth information on the thermal performance of the SOT-227 package.2

Footnotes

  1. DigiKey. SMC Diode Solutions SKIS300-200 [product page]. Retrieved 2026-04-02, from https://www.digikey.com/en/products/detail/smc-diode-solutions/SKIS300-200/25595415. ↩

  2. Microsemi. Application Note 1818 - Mounting Considerations for the SOT-227 Package [application note]. Retrieved 2026-04-02, from https://ww1.microchip.com/downloads/aemDocuments/documents/PPM/ApplicationNotes/ApplicationNotes/1818_a.pdf. ↩ ↩2

  3. IXYS (2016). DSEP2x91-03A - High Performance Fast Recovery Diode, Low Loss and Soft Recovery, Parallel legs [datasheet]. Retrieved 2026-04-02, from https://docs.rs-online.com/b2d3/0900766b815b2c64.pdf. ↩ ↩2

  4. Littelfuse (2026). Application note - Handling and Mounting Littelfuse miniBLOC - SOT227B [application note]. Retrieved 2026-04-02, from https://www.littelfuse.com/assetdocs/handling-and-mounting-littelfuse-minibloc-sot227b?assetguid=c684f512-40c9-404e-a9b9-f7c1ec28671b. ↩

  5. Vishay. Outline Dimensions - SOT-227 Generation 2. Retrieved 2026-04-02, from https://www.vishay.com/docs/95423/sot-227g2.pdf. ↩

  6. Vishay. VS-HFA140FA120 HEXFRED 140A ultrafast soft recovery diode [datasheet]. Retrieved 2026-04-02, from https://www.vishay.com/docs/94746/vs-hfa140fa120.pdf. ↩