![]() If you fail to include a copper pour and some breathing space around the LED because you didn't read the instructions it might cry, and water and electricity don't mix. You might end up with a power LED that has a third pin, electrically isolated from anode and cathode, just for removing heat. However, the footprint in the PDF is different from that described as being suitable for a resistor. So long as you use common practices (marking cathode not anode) I'm sure it will be fine.Īt the end of the day you should ALWAYS read the component datasheet. 2 The LED in question is described as 0805 dimensionally. You could just add your own graphic if you want, but don't forget some poor bugger has to make this board and he'll have no idea what your circuit does or which way round things go unless you tell him. But excercise some common sense: What's the difference between a resistor and an LED - polarity! Yes, you can use a resistor footprint, but you'll have to mark the cathode. So what's my point? I suppose it's "do whatever's easiest for you". Now have a flick through some datasheets for 0805 resistors (or any other 0805 component) from different manufacturers and see how many fit one of the above specs exactly. ![]() Red is of course the pads, but I haven't shown solder mask or paste outlines. The long lead is the anode and must be placed in the square solder pad. Strait from the WIKI for REN64XC: -The LEDs are polarized and must be installed correctly. The turquoise is silk-screen graphics and the black outlines are the "occupancy" boundaries. The short leg (the Cathode or K) of the LED must go into the square pad. The cathode (-) pins pad should be square while the anode (+). They all differ slightly, and they're all IPC. Remember that the bar should be visible even after the diode or LED is soldered to the board. Yes, that's three footprints for 0805 chip resistors, and one for an 0805 LED. This can be rectangle, round, square, or oblong. However, my PCB software (Proteus) comes with the full IPC library as well as it's own. That said, I didn't get very far into the document before my brain shut down, so I don't have any quotable sizes from the horse's PDF. It's really boring but it does give explicit naming conventions and, the reason for the answer, PCB land patterns. There is in existence the IPC-7351 standard. I realise I might be wandering off topic a bit, but if helps to answer questions from other people later on then it's worth writing. ![]() What is the correct size footprint for an 0805 chip resistor? Anyone? If we all fire up our favourite PCB design softwares I bet we'll all come back with a slightly difference answer.
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