Wednesday, 2018-06-13

*** tpb has joined #photonsdi00:00
*** RexOrCine is now known as RexOrCine|away01:51
*** se6astian|away is now known as se6astian07:16
*** Bertl_oO is now known as Bertl10:08
*** se6astian is now known as se6astian|away15:05
*** RexOrCine|away is now known as RexOrCine17:53
felix_the power sequencing for the gtp voltage rails on the te0714 seems to be against xilinx' recommendation o_O18:40
*** se6astian|away is now known as se6astian19:18
*** se6astian is now known as se6astian|away21:35
felix_uh oh, it seems that oshpark doesn't support plugged vias21:51
Bertlthat's why you do dog-bone breakouts21:54
felix_the problem isn't the bga, but the capacitors on the other side21:55
Bertlplace them around and in the middle channels21:56
felix_hm, then i'll have to move the 4u7 capacitors somewhere else21:58
felix_usually i place the 470n capacitors near the power supply vias and the 4u7 ones in the middle channels21:59
BertlI presume you are using 0201 for the 470n21:59
Bertlbtw, 470n?22:00
felix_so should i try to squeeze as many capacitors near the fpgas power vias, put the rest somewhere near the fpga and hope that it works? doesn't sound too good to me tbh :/22:00
felix_yep, the 470n are in 0201 package22:00
Bertlso they should fit between the vias then, no?22:00
felix_470n is the xilinx recommendation22:00
Kjetilyou should prioritize the GTP decoupling. The FPGA core is somewhat less senstive22:02
KjetilBut since the GTPs are at the chip edge that should'nt be to hard22:02
Bertlalso you probably have a lot of 'unused' I/Os22:03
Bertlthose banks can go with fewer capacitors22:03
felix_oh, wait, when i move the capacitor a bit to the vias it is connected to, the drc passed22:03
felix_the io banks aren't the problem; but i have quite some congestion in the middle and the gtp area22:03
felix_the tricky part on the gtps is the routing of the gtp clock22:04
felix_i hope that the soler paste won't flow into the vias, but i think this should work out; might cause some yield problems though with the soldering of the capacitors22:06
Bertlyou can still cap the vias22:06
felix_yeah, that might do the trick here. not sure how to do that in kicad yet, but i'll find out ;)22:09
felix_meh, the solder mask opening from the capacitor opens about a third of the solder mask over the via22:15
Bertlfor sure that can be adjusted22:25
felix_does oshpark manage to get the layers well aligned nowadays?22:34
felix_i've had problems with only small opening in the solder mask and not too great alignment of the solder mask layer22:36
felix_ah, with the right value for the solder mask expansion it looks much better. i guess i should go home and get some sleep...22:55
Bertlhave a good night then!23:13
*** Bertl is now known as Bertl_zZ23:48

Generated by irclog2html.py 2.13.1 by Marius Gedminas - find it at mg.pov.lt!