footprints and dimensions

[manubali]

hi, recently i started designing circuits and  while creating footprints i have many doubts. i will list them here and maybe someone can help me.
1: while checking lead diameter why there are dimensions like :
3X  0.55 (.022)
      0.46 (.018)
why there is 3x in front of them?
what does M B A M stands for? (see image)



2: how can i calculate hole size and pad diameter?
3: where can i get 3d models?

[mdszy]

Your image is fubar, do you have a datasheet with pad dimensions you're working from?

[manubali]

Your image is fubar, do you have a datasheet with pad dimensions you're working from?

yes i have datasheet for    IRF540NPBF mOSFET

[mdszy]

Okay so, the datasheet says

"Dimensions are shown in millimeters (inches)" which means the number in parentheses is inches, the number without parentheses is mm.

3x means that there are 3 pins and the indicated dimension can be anywhere from 0.55mm to 0.46mm.

I have no clue what the MBAM marker thing stands for, sorry.

[tpowell1830]

MDSZY is right, and the M in the circle is a geometric tolerancing symbol. Here are some explanations.

http://www.cobanengineering.com/GeometricDimensioningAndTolerancing/GeometricTolerancingAndSymbols.asp

[manubali]

Okay so, the datasheet says

"Dimensions are shown in millimeters (inches)" which means the number in parentheses is inches, the number without parentheses is mm.

3x means that there are 3 pins and the indicated dimension can be anywhere from 0.55mm to 0.46mm.

I have no clue what the MBAM marker thing stands for, sorry.

Thanks, can you also tell me how to calculate hole sizes and pad diameter?

[Twoflower]

Here's the package specification from Vishay for the TO-220AB: https://www.vishay.com/docs/71195/to220ab.pdf

The pins are build up a rectangle with the dimensions b x C = 1.73mm x 0.61mm. The hole diameter should be bigger than: d = sqrt(a^2 + b^2). But be careful. If you specify the drill diameter exact to that number you call for trouble. As the plating (double sided PCB) will reduce the effective diameter. See also https://www.pcb-3d.com/knowledge-base/pth-dimensions/

About the question for the 3D model: The IRF540NPBF uses a normal TO-220AB housing. I would say you'll find plenty of models out there (hint: look at the URL above)