Hello,

Currently, I am drawing SPV1020 PCB scheme in a KiCAD and I'm a little bit confused of the symbols included in the datasheet drawing. What does A (B, C, D etc.) in a box stands for? (Picture included)

Would appreciate any kind of help,
Thank you!

 

Welcome to AAC!

B looks like a dimension label. Same for A, except it may have a note. More context would help.

 

Welcome to AAC!

B looks like a dimension label. Same for A, except it may have a note. More context would help.

The weirdest part about this is that also B is in the scheme but mechanical data doesn't even show B.

 

A, B and C in boxes seem to refer to something else, but the other letters are dimensions from the table on the previous page.

 

A, B and C in boxes seem to refer to something else, but the other letters are dimensions from the table on the previous page.

Okay. But how do I find the size of the case? E seems to be right for one side but what about the other? I thought that A could stand for that but apparently not. Anything else seems not to be bound to the other side.

Also, what about this little weird "letter"? (picture included)

 

Above the case there is a 'mess' on the centre line - that is a 'D'
The weird letter you show is a lower case 'e'.
Not the best quality image I have ever seen. It is quite low resolution.
There is a better image here for a different chip although yours doesn't include the heatsink pads underneath.

 

Above the case there is a 'mess' on the centre line - that is a 'D'
The weird letter you show is a lower case 'e'.
Not the best quality image I have ever seen. It is quite low resolution.
There is a better image here for a different chip although yours doesn't include the heatsink pads underneath.

Thank you, Albert, for the link and everyone else who participated in this discussion. This will help me quite a lot!

 

I think the capital letters with what look like arrows are viewing planes that don't mean anything to EEs who'll be reading the drawings.

'C' points to the view below it, 'A' points to the view above it, 'B' points to the view to the right of 'A'. As an EE, the drawing is simple enough that I could have figured that out without the 'pointers'.


That ST datasheet could have saved a page, and be easier to read, if they put the dimensions on the drawing instead of in a table on a different page:
TI 74HCT573

 

I think it's this
https://en.wikipedia.org/wiki/Geometric_dimensioning_and_tolerancing
So the position tolerance of the pins is within 0.1 mm to reference planes A and B.