altiumdrawingfootprint
I am a new user of Altium Designer. I need to make a footprint of this varistor, and I cannot understand its drawing. Same thing happens for the rest of the components. Can someone here tell me how I am supposed to decide the pad diameter, height, width? Take this doc as a reference, and I hope I will cater other drawings as well then!
Here is the datasheet link (Littelfuse LA Varistor Series).
If an offset isn't given from the center-line or some other point, it should be symmetrical about the c.l. (always has been in my experience). So 4.7 mm between the inside of GND3/GND4 would mean they are each 2.35 mm away from the c.l., likewise with the 8.3 mm outer to outer.
The pins appear to correspond to the SD card pinout I looked up. It appears backwards on the footprint because the actual SD terminals would be on the right side, but the contacts lead to the left to connect to the board.
The 0.7 is the distance from the center of the smaller (contact) pads to the edge of the larger (mechanical) pad.
The 1.2 is the width of the larger pad.
Notice the dot both arrows point to.
edit
You'll often see the indication BSC next to one of the measurements. This means Basic Spacing between Centers and is a nominal value. Could have been given here next to the 1mm (pitch) value, or next to a 6mm value between centers of first and last pad.
Best Answer
This is what you have to draw:
Dimensions are at page 10 of that datasheet. For information regarding pads/holes What pad hole (drill) size is appropriate for a given through-hole lead diameter?