MBHP_DOUTx4: where to put the caps?

[alchemist]

Hello,

 

I am soldering a MBHP_DOUTX4 V2, but I don't see clearly where to put the 4+1 caps on the board: the photo is not clear enough, and the caps are not mentioned in the Eagle board files.

 

Thank you for the help!

[niklasni1]

The caps are normal bypass caps from the power supply line to the ground line of the ICs. These are mounted close to the chip to act as a small local current storage, so that when the chip suddenly draws a lot of current (like when it switches state), it can get some of it very quickly from the capacitor. This helps keep the power supply smoother in the circuit. (At least, this is my meagre understanding of it.)

 

For all 74xx logic ICs like the shift registers on the DOUT modules, if you look at the chip so pin 1 is top left, the power supply pin is the top right pin, and the ground is the bottom left. The docs also specify a cap from the main power input to the main ground pin.

[alchemist]

OK, I think I see what to do.

 

Thank you for the reply :)