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Topic: Question on SMT part packaging? (Read 999 times) previous topic - next topic



I've made a little board in Eagle using parts from the SFE and Adafruit libraries and I'm ordering parts from Digikey. I wan't to make sure I'm ordering the right parts.

On the BOM I have part C1:

Part Value         Device                Package           Description
C1   10uF          CAP_POL1206           EIA3216           Capacitor Polarized

and another 10uF capacitor:

Part Value         Device                Package           Description
C6   10uF          CAP1206               1206              Capacitor   

Under "Device" both of the caps are 1206, but for package C6 is 1206 and C1 is EIA3216, which from my understanding means they're both the same, where 1206 is imperial and 3216 is metric. So could I buy this capacitor (http://www.digikey.com/product-detail/e ... ND/2103160) and use it for both C1 and C6?

Thanks for the help!


They both appear to be the same value & size.  Is the voltage different?    If they are the same, usually they are listed once on the BOM, with a quantity required and the reference designators (C1 & C6).

If the voltage is different, you can always use the higher-voltage part in both places (since they are the same size).

If it was me, as a hobbyist I'd try to have the parts in-hand before completing the board design and having it made.  At work, we don't always have the parts, and nobody is physically checking & measuring the parts that we do have in stock.  But, our board designer has quite a bit of expereince.    Sometimes we get a part-size wrong, but we can usually
"make it work" on the prototype boards and get it corrected when we go into production.   


You can design the pad layout for caps and resistors to fit more than one size of chip
component - say both 1206 and 0805, but making the pads a bit longer.  However this may
mean there won't be room for trace to go between them (1206 is useful for this reason!).

For hand-assembly I tend to stick to 0805 and 1206 sizes to make component placement
easier (and easier to find if you drop one - 0603 is crazy!)
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]


Same here - I don't like using smaller than 0805 if we will be placing parts by hand.
Automated pick & place assembly? I'll go right down to 0402 for caps and pullup resistors.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

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