I am thinking about trying BatchPCB and so I entered its “design rules” into Eagle (got these from the BatchPCB web site) to render the board and one thing I noticed right away is that the minimum pad spacing of 8mils is too wide for the pads on a TQFP-100 chip.
Does BatchPCB support TQFP?
Thanks!
TQFP is 0.5mm pin to pin, which fits fine with 8mil trace/spacing.
8mil is only 0.2032mm.
Your math is right, and at first I thought I had pulled the wrong footprint. But I checked it and also the TQFP-100 in the Atmel-2005 Eagle library. The pin center-to-center spacing is .5mm, but the pads are drawn bigger leaving only .15mm between the pads, which is < 8mil.
I’m a bit concerned about changing the recommended pad size… if you have actually used BatchPCB for TQFP-100 or other TQFP chips please chime in with details!
I’d love to use BatchPCB, but there are other more “traditional” vendors out there who will do 4mil spacing…
Thanks!
There’s no more details here. Reduce the pad size. It works fine.
For reflow soldering the pad width should be 0.3 mm, according to the IPC standards. That gives 0.2 mm between pads.
Leon
This is a one off. It’s not rocket science. Reduce the pad width to 2.9mm.
TQFP, LQFP, QFN, it all works fine.
Thanks for the info Mark! I’m just trying to be very careful with my first TQFP-100, Nice work on that board!
I’m doing a EQFP-144 (Cyclone III, 3C16) and the bot hasn’t complained yet. I haven’t actually built one up yet, however.
