TO-277A (SMPC) Component Package


Name (JEDEC) TO-277A (Transistor Outline 277A)
  • SMPC (Vishay)
Variants n/a
Similar To n/a
Mounting SMD
Pin Count 3 (2 pins + 1 pad)
    2.13mm (between pins 1 and 2, excluding the pad (pin 3))
Solderability A little tricky to solder by hand, as this package has a pad. However, since the pad comes right to the edge, it can be done with a large and hot enough soldering iron tip. Easy to solder with with infrared or reflow techniques.
Thermal Resistance
  • $$T_{JC} = 3^{\circ}{\rm C}/W$$
  • $$T_{JA} = 60^{\circ}{\rm C}/W$$ (recommended land pattern, no thermal vias)
Physical Dimensions
  • Package Size: 4.60×6.50×1.10mm (width*length*height)
  • Recommended Footprint Land Area: 4.8×6.8mm = 32.6mm2
3D Models
Common Uses
  • Medium/high power diodes.


Used by Vishay and Bruckewell.

3D Renders

A 3D render of the TO-277A component package.
A 3D render of the TO-277A component package.


Dimensions and land pattern for the TO-277A (SMPC) component package.

Posted: April 7th, 2015 at 1:06 pm
Last Updated on: December 27th, 2016 at 6:06 am

  • Saikrishna Kashyap Gundlapalli

    the clearance seems to be a problem. Only 0.8mm between anode and cathode. How can it block 600V?

    • Good question, and I don’t know the answer! If you use the recommended layout (as I have added above), the clearance drops to only 0.68mm.

      • Saikrishna Kashyap Gundlapalli

        Hi, Thanks for the reply. I am not able to see your recommendation for layout

        • It’s the lower right quadrant labelled “Mounting Pad Layout” in the image in the above page under the heading “Dimensions”.

          • Saikrishna Kashyap Gundlapalli

            0.68mm that you calculated is between two bottom pins which are of same terminal (anode). We need the clearance between the third pad (bigger one) and the bottom two pins which is coming down to 0.81mm. I still don’t understand how it can block 600V.