Does BatchPCB allow QFN packages?

Archive BatchPCB
1

I have a design that uses an AT90USB82 which is a QFN…(http://www.atmel.com/dyn/resources/prod … oc7707.pdf)

and an nRF2401… (http://www.sparkfun.com/datasheets/RF/nRF2401rev1_1.pdf)

Both are packages that have pin clearances less than 8 mil. The pins have approximately .199mm of clearance.

I have another chip with about the same clearance.

Are these chips too small? The pin clearance is less than 8 mil, but they are packages that are fairly common for development.

Is BatchPCB able to do these small clearance chips, or should I find another PCB house?

Thanks

Shaun

2

This is a good question, one i’d like to know too… I have made a few QFN parts in my librarys and every time i’ve had a few issues with Sparkfun’s DRC…

3

As long as it passes the 8mil DRC check then you can have anything you like.

4

I have a design that uses the ATtiny24 QFN chip that’s being produced with BatchPCB. I created the footprint in Eagle from the design drawings in the datash33t, and though the pads are very small, they barely have 8 mil spacing. I think as long as you can get it to pass using sparkfun’s DRC file, you should be fine.

5

Hi Shaun,

I was wondering if/how you resolved this issue. I am looking at the exact same thing, same parts even. Have you seen the avrusbrf01? I’m basically trying to recreate that part.

At this point, I think I will try to shave off a little on the QFN footprint pads to make the 8mil drc spacing happy. If you’ve ( or anyone else ) have already done this, please let me know.

Thanks.

Charlie

6

If you have less than 16mil from the centre of one pad to the centre of the next pad, then you are out of luck. The only option you have is moving to the 4 layer service, which allows 6mil trace/spacing, or going with another service.

I have a part here with 0.4mm leads and reducing the pads to the minimum 8mils means I still have a tiny but less than 8mils spacing between the parts. I just can’t use that part with batchPCB. Funny thing is, I can make this board myself with regular toner transfer, but I was hoping to have something a little more professional looking to show off.

7

I just looked at the datasheet. The contact spacing on the QFN part looks like it’s 0.5mm, which will work with the 8mil design rule, if you just reduce the size of the pads.

8

I’ve run several boards with QFN packages through BatchPCB with no issues. The DRC-happy land pattern differs very little from manufacturer recommended one.