On 2023-01-10 gnuarm.del...@gmail.com wrote in comp.arch.fpga:> On Monday, January 9, 2023 at 7:30:34 PM UTC-5, Stef wrote: >> On 2023-01-09 gnuarm.del...@gmail.com wrote in comp.arch.fpga: >> > >> > I'm trying to be as conservative as possible. I'd rather not use BGAs at all, but the only QFPs I can find that fit on the board are Gowin, which is not on the approved vendor list with my customer. They are too Chinese. >> > >> Digikey has a number of FPGAs in QFP100/144 in stock. Efinix, >> Microchip, Lattice, Xilinx. Nothing that suits your needs? > > The QFP144 is far too large. Efinix has no QFP100 parts. Lattice has no QFP100 parts that I've seen since the LFXP parts revision 2.0 of my board used. Xilinx has not had any in decades, unless you mean the very small, yet expensive CPLD thing they sell. Microchip might have some QFP100 parts in one of their older lines that I'm not so familiar with. I believe their logic cells can be either logic, or FFs, but not both. So you need roughly double the count, if not more. They are very expensive too. I've never been inclined to research such an old product, much like the Spartan 3. I get that in a QFP100, but how long will they continue to make Spartan 3 devices... which have also climbed significantly in price. It's what is called NRND. Gowin would have been perfect, but at one point they were put on a US list of CCMC (Communist Chinese Military Companies). Even though they were taken off, my customer sells a lot to the US government, so they don't like the "optics". > > Did I miss any?Okay, QFP144 is too large, that severily limits the QFP options, but Lattice does have a QFP100: ICE40HX1K-VQ100. But this one may not have enough logic for you, its the smallest in the series. -- Stef Rube Walker: "Hey, Yogi, what time is it?" Yogi Berra: "You mean now?"
PCB Layout for BGAs
Started by ●January 7, 2023
Reply by ●January 10, 20232023-01-10
Reply by ●January 10, 20232023-01-10
On Tuesday, January 10, 2023 at 3:52:54 AM UTC-5, Stef wrote:> On 2023-01-10 gnuarm.del...@gmail.com wrote in comp.arch.fpga: > > On Monday, January 9, 2023 at 7:30:34 PM UTC-5, Stef wrote: > >> On 2023-01-09 gnuarm.del...@gmail.com wrote in comp.arch.fpga: > >> > > >> > I'm trying to be as conservative as possible. I'd rather not use BGAs at all, but the only QFPs I can find that fit on the board are Gowin, which is not on the approved vendor list with my customer. They are too Chinese. > >> > > >> Digikey has a number of FPGAs in QFP100/144 in stock. Efinix, > >> Microchip, Lattice, Xilinx. Nothing that suits your needs? > > > > The QFP144 is far too large. Efinix has no QFP100 parts. Lattice has no QFP100 parts that I've seen since the LFXP parts revision 2.0 of my board used. Xilinx has not had any in decades, unless you mean the very small, yet expensive CPLD thing they sell. Microchip might have some QFP100 parts in one of their older lines that I'm not so familiar with. I believe their logic cells can be either logic, or FFs, but not both. So you need roughly double the count, if not more. They are very expensive too. I've never been inclined to research such an old product, much like the Spartan 3. I get that in a QFP100, but how long will they continue to make Spartan 3 devices... which have also climbed significantly in price. It's what is called NRND. Gowin would have been perfect, but at one point they were put on a US list of CCMC (Communist Chinese Military Companies). Even though they were taken off, my customer sells a lot to the US government, so they don't like the "optics". > > > > Did I miss any? > Okay, QFP144 is too large, that severily limits the QFP options, but > Lattice does have a QFP100: ICE40HX1K-VQ100. But this one may not have > enough logic for you, its the smallest in the series.No, that is too small. They also have a QFN84, which unfortunately is two rows, requiring finer than 0.1 mm trace/space. Again, only supporting the 1K size, and oddly enough, no support for the PLL. The current design is 3 kLUTs at 90% utilization. I was surprised it fit. I don't want to squeeze a new design so tightly, and I need to add some logic, so I'm shooting for at least a 5 kLUT part and prefer larger. The current design has uLaw and I'd like to be able to add Alaw, not that it's a lot of logic, but it's something more than a couple of LUTs. Then there's the multipliers... the current design uses one multiply, done using LUTs. I've been asked to provide gain controls, requiring two more multipliers, 16 x 8 minimum. This could be done by shift and add, so not horribly large. But built in multipliers would help with the size and the iCE40 line has none. Oddly enough, many of the Lattice lines (even relatively modern ones) have no multipliers. The entire XO3 line has no multipliers. The MachXO3D has a couple of parts in an QFN72 with enough I/Os (barely), but not much availability. Hmmm... this may have improved. The MachXO3D-9400 has enough inventory in various configurations to do the initial order. But the I/O count on the QFN72 probably won't be enough with the added features. Ignoring that, the current inventory might get me through the current order, but 53 weeks for any further inventory. Digikey tells you more are coming in April. When you enter a number, it's always available in April, even a million. -- Rick C. ++ Get 1,000 miles of free Supercharging ++ Tesla referral code - https://ts.la/richard11209
Reply by ●January 10, 20232023-01-10
On Tue, 10 Jan 2023 06:19:58 -0800 (PST) "gnuarm.del...@gmail.com" <gnuarm.deletethisbit@gmail.com> wrote:> But built in multipliers would help with the size and the iCE40 line has none.Just four or eight multipliers, and many more on-chip goodies: https://www.latticesemi.com/en/Products/FPGAandCPLD/iCE40UltraPlus dev board https://tinyvision.ai/collections/kits/products/upduino-v3-1 Jan Coombs --
Reply by ●January 10, 20232023-01-10
On 2023-01-09, gnuarm.del...@gmail.com <gnuarm.deletethisbit@gmail.com> wrote:> > I'm concerned about adding cost for the boards, cost for the assembly and > just an easy road forward. I spend the last two years building 8,000 > units when the CODEC factory burnt down. The customer knows about this > issue, but the previous CM turned flaky on me and all but stopped > delivering product. > > I have a new CM, but I don't want to go through production problems again.0.8mm BGA should be no problem for any reputable CM - fine-pitch QFP is usually more trouble.> JLCPCB does 0.2 mm holes without extra charge, along with 0.45 mm via > pads. They charge a bit extra for 0.4 mm pads. I guess it makes for a > smaller target. I look at various PCB maker's pages to see what they > state they can do.That should be enough to fit a via between the 0.8mm-BGA pads - that's what we do regulary. If you want blocking caps underneath the BGA, you will probably require plugged/plated vias. You will have to look at the pinout and do the fanout routing to see how many layers you need. Talk to your PCB manufacturer about the details before doing the final layout - there is some fine tuning (eg. drill size, annular ring, spacing) where different PCB manufacturers have different preferences regarding which rules will yield good results - when doing do, 0.8mm BGA should be possible at modest PCB costs. cu Michael -- Some people have no respect of age unless it is bottled.
Reply by ●January 10, 20232023-01-10
On 2023-01-10, gnuarm.del...@gmail.com <gnuarm.deletethisbit@gmail.com> wrote:> > The QFP144 is far too large. Efinix has no QFP100 parts. Lattice has no > QFP100 parts that I've seen since the LFXP parts revision 2.0 of my board > used.We have used Lattice MachXO2 in TQFP100 in the past - not sure if these fit your needs.> At this point, I'd be happy with the Xilinx XC7S15-1FTGB196I.Okay, this sounds like the MXO2 might be two sizes to small for you. cu Michael -- Some people have no respect of age unless it is bottled.
Reply by ●January 10, 20232023-01-10
On Tuesday, January 10, 2023 at 12:33:54 PM UTC-5, jan Coombs wrote:> On Tue, 10 Jan 2023 06:19:58 -0800 (PST) > "gnuarm.del...@gmail.com" <gnuarm.del...@gmail.com> wrote: > > > But built in multipliers would help with the size and the iCE40 line has none. > Just four or eight multipliers, and many more on-chip goodies: > > https://www.latticesemi.com/en/Products/FPGAandCPLD/iCE40UltraPlus > > dev board > https://tinyvision.ai/collections/kits/products/upduino-v3-1Yes, sorry, they do make a few multiplier chips with FPGA tiles. I was referring to parts that I might be able to use. They have a couple of 8 kLUT parts, only one in a package that I could use. I can pick between a 0.8 mm ball pitch, or 0.65 mm. Not really excited about either, even though there's a bit of inventory of the 256 ball, 0.8 mm part. But no insight into future deliveries. This looking for usable parts gets old fast, and I've been doing it for over a year now. When I find the guy responsible for this shortage, I'm going to give him a piece of my mind! -- Rick C. --- Get 1,000 miles of free Supercharging --- Tesla referral code - https://ts.la/richard11209
Reply by ●January 10, 20232023-01-10
On Tuesday, January 10, 2023 at 1:35:24 PM UTC-5, Michael Schwingen wrote:> On 2023-01-09, gnuarm.del...@gmail.com <gnuarm.del...@gmail.com> wrote:==20> >=20 > > I'm concerned about adding cost for the boards, cost for the assembly a=nd=20> > just an easy road forward. I spend the last two years building 8,000=20 > > units when the CODEC factory burnt down. The customer knows about this==20> > issue, but the previous CM turned flaky on me and all but stopped=20 > > delivering product.=20 > >=20 > > I have a new CM, but I don't want to go through production problems aga=in.> 0.8mm BGA should be no problem for any reputable CM - fine-pitch QFP is==20> usually more trouble.Part of my problem is a lack of having designed with BGAs before. I can fi= nd footprint recommendations, but they are different for every manufacturer= . It didn't occur to me that this might be because even though they have = the same pitch and ball count, they may not have the same ball size. =20 The two primary choices right now are a 196 ball, 1.0 mm pitch and 256 ball= , 0.8 mm pitch. Can you share the design rules you used for these parts?= =20> > JLCPCB does 0.2 mm holes without extra charge, along with 0.45 mm via==20> > pads. They charge a bit extra for 0.4 mm pads. I guess it makes for a==20> > smaller target. I look at various PCB maker's pages to see what they=20 > > state they can do. > That should be enough to fit a via between the 0.8mm-BGA pads - that's wh=at=20> we do regulary. If you want blocking caps underneath the BGA, you will=20 > probably require plugged/plated vias. You will have to look at the pinout==20> and do the fanout routing to see how many layers you need.=20 >=20 > Talk to your PCB manufacturer about the details before doing the final=20 > layout - there is some fine tuning (eg. drill size, annular ring, spacing=)=20> where different PCB manufacturers have different preferences regarding wh=ich=20> rules will yield good results - when doing do, 0.8mm BGA should be possib=le=20> at modest PCB costs.=20You mean my CM who orders the PWBs? Yeah, I've tried asking before and the= y say they would need a design so they could get a quote. I know, that sou= nds lame, but I used four different CMs over the last decade and they have = all said the same thing. They don't have design rules, that's for me to kn= ow.=20 --=20 Rick C. --+ Get 1,000 miles of free Supercharging --+ Tesla referral code - https://ts.la/richard11209
Reply by ●January 10, 20232023-01-10
On Tuesday, January 10, 2023 at 1:39:43 PM UTC-5, Michael Schwingen wrote:> On 2023-01-10, gnuarm.del...@gmail.com <gnuarm.del...@gmail.com> wrote:==20> >=20 > > The QFP144 is far too large. Efinix has no QFP100 parts. Lattice has no==20> > QFP100 parts that I've seen since the LFXP parts revision 2.0 of my boa=rd=20> > used. > We have used Lattice MachXO2 in TQFP100 in the past - not sure if these f=it=20> your needs. > > At this point, I'd be happy with the Xilinx XC7S15-1FTGB196I. > Okay, this sounds like the MXO2 might be two sizes to small for you.I have the Lattice selection guide, the Lattice package guide, Lattice data= sheets and have marked all the packages I might use on all the parts I mig= ht use. =20 No, the MXO2 parts are pretty limited for this. The existing design is sho= ehorned into the 3 kLUT XP part. I was surprised it routed. I have to add= some logic and I don't have the same confidence in routing, so I want plen= ty of room in this part. 5 kLUTs should do the job, but I'd like to have a= bit more. The Xilinx part has 6000 LCs, but there is no such thing as a L= C in a Xilinx part, that's a marketing term. The XC7S6 has 3,752 6LUTs and= twice that many FFs, so it should be about like an 8 kLUT device, but who = knows if the routing is up to it. The only one in stock is the XC7S15, so = that's the one I would use, at least to start. But I need a better price t= han the $25, and some expectation of getting more parts.=20 Anyone see signs of the shortages easing?=20 --=20 Rick C. -+- Get 1,000 miles of free Supercharging -+- Tesla referral code - https://ts.la/richard11209
Reply by ●January 11, 20232023-01-11
On 10/01/2023 23:17, gnuarm.del...@gmail.com wrote:> > Yes, sorry, they do make a few multiplier chips with FPGA tiles. I > was referring to parts that I might be able to use. They have a > couple of 8 kLUT parts, only one in a package that I could use. I > can pick between a 0.8 mm ball pitch, or 0.65 mm. Not really excited > about either, even though there's a bit of inventory of the 256 ball, > 0.8 mm part. But no insight into future deliveries. > > This looking for usable parts gets old fast, and I've been doing it > for over a year now. When I find the guy responsible for this > shortage, I'm going to give him a piece of my mind! >The reason you can parts in high-density packages, but not low-density packages, is that there are lots of people such as yourself who are so reluctant to use the small pitch devices. (This is not criticism - you have solid reasons for preferring larger pitch devices, as do many others.) Big manufacturers often prefer smaller pitch and higher density, as it can lead to lower overall costs for their products, even if design is more costly and the pcbs are more expensive. There have been component supply issues for several years now, with only gradual improvement in many areas. But there is a general pattern of somewhat higher availability in smaller pitch parts.
Reply by ●January 11, 20232023-01-11
On 10/01/2023 23:44, gnuarm.del...@gmail.com wrote:> On Tuesday, January 10, 2023 at 1:35:24 PM UTC-5, Michael Schwingen > wrote: >> On 2023-01-09, gnuarm.del...@gmail.com <gnuarm.del...@gmail.com> >> wrote: >>> >>> I'm concerned about adding cost for the boards, cost for the >>> assembly and just an easy road forward. I spend the last two >>> years building 8,000 units when the CODEC factory burnt down. The >>> customer knows about this issue, but the previous CM turned flaky >>> on me and all but stopped delivering product. >>> >>> I have a new CM, but I don't want to go through production >>> problems again. >> 0.8mm BGA should be no problem for any reputable CM - fine-pitch >> QFP is usually more trouble. > > Part of my problem is a lack of having designed with BGAs before. I > can find footprint recommendations, but they are different for every > manufacturer. It didn't occur to me that this might be because even > though they have the same pitch and ball count, they may not have the > same ball size. > > The two primary choices right now are a 196 ball, 1.0 mm pitch and > 256 ball, 0.8 mm pitch. Can you share the design rules you used for > these parts? >The board stackup, routing and bypassing recommendations from FPGA manufacturers are basically bollocks. I believe it is primarily a matter of being able to fob off complaints and support requests by saying "Did you follow our layout application notes, impossible though they may be? If not, it's not /our/ fault that you have problems." OK, that's a bit of an exaggeration, but you can ignore the suggestions of 16 layers with 8 different power planes and a dozen different capacitor sizes mounted directly below the device. Yes, there are complications for BGA layouts. And I'm afraid you are going to have to do some research, some learning, and some discussions with both PCB manufacturers (or their proxies) and board builders. For the same pitch of BGA, there can be different sized balls, and different sized pads on the underside of the BGA device which will affect the shape of the ball after soldering. Pad size on the pcb has different options. You have a key decision between solder mask defined and non-solder mask defined pads, which affects mechanical strength, thermal stability, solder paste masks, routeability, and manufacturing requirements. And BGA soldering has different requirements in production than non-BGA devices. I have no doubt that this is something you can master quite quickly - it's not /that/ hard. But it's not something you can learn just by a thread on a newsgroup.
