Re: [ARTIQ] ARTIQ 1.0rc1
On Tuesday, 29 March 2016 11:30:09 PM HKT Aaron Hankin wrote: > Conda currently downloads commit id 1c9b8a1 from 10 days ago. > Should we be pulling the latest code from git for testing of release > candidate or is this behavior unintentional? We will make another release candidate soon which will contain the fixes for the issues found in 1.0rc1. Before that, yes, 1.0rc1 stays 1.0rc1. Sébastien ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
Re: [ARTIQ] analog extension cards
I can agree that FMC is not the best idea in case of RF stuff. There are multipin RF board 2 board coaxial connectors which can be used for plugin modules. And such modules can be easily shielded using i.e. Wurth shields or EZ-Shields from Harwin that can be easily customized. Greg -Original Message- From: ARTIQ [mailto:artiq-boun...@lists.m-labs.hk] On Behalf Of Slichter, Daniel H. (Fed) Sent: Saturday, March 26, 2016 4:40 PM To: Sébastien Bourdeauducq ; artiq@lists.m-labs.hk Subject: Re: [ARTIQ] analog extension cards To clarify nomenclature, we have been referring to these as "RF daughter cards" previously. These cards could potentially contain components such as RF amplifiers, operational/instrumentation amplifiers, filters, mixers/modulators/demodulators, splitters/combiners/hybrids, baluns, digital or analog attenuators, RF switches, frequency multipliers. There are three types of basic card designs that I think should be available from the beginning: 1. "Low frequency" - Signal bandwidth of a few MHz, swinging between +/- 10 V or so, suitable for ion trap transport waveforms or various DC or quasi-DC bias signals in general applications. This would involve op amps/instrumentation amps running off +/- 15V supplies in a similar configuration to the current PDQ output stages. Footprints for discrete component filters both before and after the amplifiers should be included. 2. "RF" - For synthesis of tones from a few MHz out to ~3.3 GHz, suitable for AOM drive or Be+/Mg+/Ca+/NV center microwave transitions. This would involve a set of filters (common footprint, stuff boards with different cutoff parts to define band of interest -- these can be left open for users, or we can choose one or two basic frequency sets and they can run their own custom assembly order from the fab/layout docs if they want something different) followed by an RF amplifier stage (ERA-4SM is a good broadband low-phase-noise selection), a digital step attenuator, and a fast high-isolation RF switch. 3. "Upconverting" - For synthesis of tones beyond ~3.3 GHz, suitable for Yb+ or superconducting qubit microwave transitions. The board would have an input connector for an externally generated microwave carrier, split and sent to the LO ports of a set of mixers/modulators. We should decide if these needs to be IQ mixers or if regular mixers are sufficient. There will be filters (again, common footprint for a choice of frequencies) between the DAC outputs and mixer IF ports. Each mixer RF port will be followed by an amplifier, a digital step attenuator, and a fast high-isolation RF switch. Again, I stress strongly that I am *not* satisfied using FMC connectors for these cards until someone has tested and verified properties like crosstalk. This issue has the potential the render the entire hardware project useless (e.g. if crosstalk levels are too high), and therefore we need to be very careful about design here. For the "RF" and "upconverting" boards, it will most likely be important to have board-level shielding cavities to reduce crosstalk between channels on the daughtercards. It is possible to have these custom designed and produced inexpensively at scale (~$15-$20/board). Best, Daniel > -Original Message- > From: ARTIQ [mailto:artiq-boun...@lists.m-labs.hk] On Behalf Of > Sébastien Bourdeauducq > Sent: Saturday, March 26, 2016 2:57 AM > To: artiq@lists.m-labs.hk > Subject: [ARTIQ] analog extension cards > > Hi, > > any ideas of what analog extensions in FMC form factor for the DSP > card should be available first? Mixers I guess, but what are the specs? > Amplifiers? > > Sébastien > > ___ > ARTIQ mailing list > https://ssl.serverraum.org/lists/listinfo/artiq ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
Re: [ARTIQ] FW: initial specification of the project
FMC has mounting height of 8 or 10mm. Other heights are also possible in case of SEARAY series, but one must order large number of them Greg -Original Message- From: ARTIQ [mailto:artiq-boun...@lists.m-labs.hk] On Behalf Of Slichter, Daniel H. (Fed) Sent: Tuesday, March 29, 2016 10:39 PM To: Robert Jördens Cc: Grzegorz Kasprowicz ; artiq@lists.m-labs.hk Subject: Re: [ARTIQ] FW: initial specification of the project Let me make clear that I don't have any specific opposition to FMC for the power/digital signals. The only reason for considering other types of connectors would be either if the desired stackup height is not doable (this is unlikely -- one .224" bullet e.g. corning A1A1-0001-02, plus two male connetors with .051" reference plane distance, e.g. Molex 74315-3312, gives a total SMP height of 8.28 mm, which works perfectly with the standard FMC stackup height of 8.5 mm board to board), or if there is not enough real estate on the board to meet the physical footprint requirements (FMC is larger than the QSE connectors I sent along, for example). > -Original Message- > From: Robert Jördens [mailto:r...@m-labs.hk] > Sent: Tuesday, March 29, 2016 11:08 AM > To: Slichter, Daniel H. (Fed) > Cc: Sébastien Bourdeauducq ; Grzegorz Kasprowicz > ; artiq@lists.m-labs.hk > Subject: Re: [ARTIQ] FW: initial specification of the project > > On Tue, Mar 29, 2016 at 5:16 PM, Slichter, Daniel H. (Fed) > wrote: > > Yes, FMC could work but it's overkill in terms of pin count; one > > might be > able to find a smaller footprint connector with fewer pins, which > would be advantageous. Frankly something as dumb and cheap as 2 mm > pin headers would do the job. > > Yes. A pin header would be dumb if there are better suggestions. > LPC FMC with 64 single ended signals is definitely not overkill if 40 > signals is the estimated need. The grounding is unlikely to hurt. > There are certainly many other offers. But if there is such a strong > opposition to FMC, I would look for something where we can at least > expect a long term availability that is similar to the FMC usage lifespan. ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
Re: [ARTIQ] FW: initial specification of the project
Let's talk about RTMs. I see your point about connector placement, but one can always use patch panels for RF signals and have them available from front side. I proposed RTMs because: - they can be used immediately with existing OSHW carriers like AFC/AFCK. So we could have working solution with good performance without excessive risk - the cost of RTM development/production is much lower than FPGA board. Of course AMC+RTM is more expensive than AMC itself, but remember about development costs. - they provide perfect isolation between noisy AMC boards and analog domain zone with independent supply. - it could be hard to fit FPGA, supply, DACs and several RF modules, all on single dual width AMC, especially when shielding is required. RTM relaxes these constraints. - on AMC+RTM you can place 8 ADC channels + 8 DAC channels + 8 RF modules. In case of single AMC board it would be hard to achieve such channels density. I simply afraid of the level of noise generated on AMC, also from neighbouring AMCs. Remember that on the same board we have DC/DCs, FPGA and some other stuff. All small signal RF systems we did were developed on RTMs and it is correct place for them. It is probably possible to achieve good results with DACs and RF modules on AMC, but requires much more work, simulation and iterations. All depend what you really need. Joe sent me some comments about noise performance of early version of RTM backplane which seems not sufficient for us. Could you give me some numbers that are required by such AMC-DAC board? i.e. channel separation @ frequency, SFDR, inter-channel phase matching@frequency. Greg -Original Message- From: ARTIQ [mailto:artiq-boun...@lists.m-labs.hk] On Behalf Of Slichter, Daniel H. (Fed) Sent: Saturday, March 26, 2016 5:06 PM To: Sébastien Bourdeauducq ; Grzegorz Kasprowicz Cc: artiq@lists.m-labs.hk Subject: Re: [ARTIQ] FW: initial specification of the project > > * we want to avoid RTMs and instead put the DAC/ADCs on the AMC card > > and have analog plug-ins using the FMC form factor (see my document). > > **Are you sure you would get noise performance from such setup that > > satisfies you? > > Unless the FMC connector is particularly bad with analog signals, I > think it should not be worse than the current hardware. I want to repeat what Sebastien has said, that we want the signals to come out the front, and to avoid the use of RTMs as the standard output. There may be some special use cases (e.g. many channels of slow ADC) that *might* work with the RTM architecture, but for the DSP AMC cards we want all the DACs on the AMC card and their outputs routed immediately to the small RF/analog daughter cards. I want to stress again that the levels of channel crosstalk relevant to quantum information/optical clock experiments are vastly more stringent than for typical signals propagating through large "high-speed" connectors. I think it will be necessary to use minimal length unshielded traces and have multi-cavity shielding on the daughtercards to ensure low crosstalk. The use of a connector like an FMC, even with grounding wires between differential pairs, is inevitably going to be worse than using dedicated board-to-board RF connectors like SMP/GPO or their smaller cousins GPPO/G3PO. These connectors are explicitly designed for these types of applications, and allow for board misalignments etc. The cost savings from using FMC, which might amount to $50 per AMC, are not worth if the crosstalk will make the cards not useful for researchers. For reference, Samtec offers an intermediate solution called Isorate, which is designed to have higher isolation than typical high speed connectors while being cheaper than SMP. They spec 80 dB isolation at 1.3 GHz and 70 dB at 7.6 GHz, so probably we are talking between 90 and 75 dB isolation in our frequency range of interest for RF/microwave signals. Best, Daniel ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
Re: [ARTIQ] FW: initial specification of the project
There are FMC-type connectors with much smaller number of pins (SEARAY series) Greg -Original Message- From: ARTIQ [mailto:artiq-boun...@lists.m-labs.hk] On Behalf Of Robert Jördens Sent: Tuesday, March 29, 2016 1:01 PM To: Sébastien Bourdeauducq Cc: Grzegorz Kasprowicz ; artiq@lists.m-labs.hk; Slichter, Daniel H. (Fed) Subject: Re: [ARTIQ] FW: initial specification of the project On Tue, Mar 29, 2016 at 11:56 AM, Sébastien Bourdeauducq wrote: > On Monday, 28 March 2016 6:30:52 PM HKT Slichter, Daniel H. (Fed) wrote: >> Thus for the two examples above, using digital connectors with a 9 mm >> or 11 mm total stackup height would give 250 um axial misalignment >> (.010"), which is a typical tolerance one would want to use anyway with SMP. >> >> More information is available in this application note: >> https://www.corning.com/media/worldwide/coc/documents/applications/mi >> crowave >> ApplicationNotes.pdf > > OK. Then mixing SMP with something else is fine IMO. The other connector can well be FMC. We need at least ~40 signals other than the analog ones going to the cards. A bunch of different power supplies, SPI control lines, identification buses, switching, attenuation settings etc. Also since reliably reflowing SMP connectors manually to three hair widths is rather tricky, manual assembly is of the table now anyway. And FMC give us at least a form factor that has been tested very well. No need to reinvent the mezzanine here. ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
Re: [ARTIQ] FW: initial specification of the project
On Friday, 25 March 2016 12:24:02 PM HKT you wrote: > * whether or not we use Zynq remains to be decided. > **The price difference is not that high (a few tens of $) and we get > plenty of CPU power Yes, but Zynq chips are annoying to program (even if we do not use the ARM cores) and more proprietary. The question is really whether the Zynq architecture has technical benefits to the end application that justify the trouble. The answer is not straightforward, e.g. CPU power doesn't translate linearly to latency reductions. [GK] If you don't use ARM, you still get hardened SDRAM controller and GBE MACs. Maybe we should do a quick experiment and map the ARTIQ RTIO core in the address space of a Zynq device, and compile (with just gcc or clang, not the ARTIQ compiler) the equivalent of the current runtime+kernel system that measures the maximum pulse rate. Then we have hard numbers to discuss. [GK]For time critical apps, one can program these CPUs bare metal. We did it in our projects. > * transceivers on the backplane are acceptable but not necessary; > since we have multiple signals we can transmit a clock and use the > regular IOSERDES to lower FPGA requirements. > **Well, IOSERDES can go up to 1.2Gbit n synchronous mode. > **GTH can go 12Gbit/s easily > **Are you sure you want to relay only on IOSERDES? Yes, I think they would be sufficient. The bulk of the data will be processed locally on-the-fly by the AMC cards, and a couple Gbps (I suppose we can route extra pairs easily) of bandwidth should be plenty for controlling the AMCs. > * what is the other large BGA chip on the MCH rendering? Is it the > Macom > M21048 48x48 crossbar? Let's not use such a device, which looks > unnecessary, complicated, and very proprietary. There isn't even a > public datasheet for it. > We do not need direct communication between the AMCs. > > **At the moment not, but remember that it's going to be research > platform If we use the IOSERDES, the FPGA has plenty of IO pins to perform such direct routing (on wider buses and/or with less bandwidth) . [GK] That' true > **I can make an option with this chip not mounted. I simply see > another potential of this board and the place on the PCB does not cost > single $ since we have to use standard module **dimensions:) OK, but what about the additional routing difficulty, and any additional PCB layers? [GK] It will need 2 extra layers What is the other application you are thinking of? [GK] The other application is not related to ARTIQ project - we will need it for another project at the WUT related with GEM detectors. [GK] Generally, it is detector processing electronics > **In case of the datasheet, I got it easily after I signed the NDA. The fewer NDAs I sign, the better. And it would make the board less accessible. [GK] I understand your point. It is not compatible with Open Hardware > * we want to avoid RTMs and instead put the DAC/ADCs on the AMC card > and have analog plug-ins using the FMC form factor (see my document). > **Are you sure you would get noise performance from such setup that > satisfies you? Unless the FMC connector is particularly bad with analog signals, I think it should not be worse than the current hardware. [GK] All depends how you deliver the clock for such DAC. This is the weakest point of such solution. [GK] Is current HW fully sufficient in terms of SFDR? Greg ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
Re: [ARTIQ] FW: initial specification of the project
One can always use 2mm or 1.27mm pin headers. 1.27 are quite fragile, but 2mm should be fine and are easily available. Greg -Original Message- From: Slichter, Daniel H. (Fed) [mailto:daniel.slich...@nist.gov] Sent: Tuesday, March 29, 2016 11:34 PM To: Grzegorz Kasprowicz ; 'Robert Jördens' Cc: 'Grzegorz Kasprowicz' ; artiq@lists.m-labs.hk Subject: RE: [ARTIQ] FW: initial specification of the project > FMC has mounting height of 8 or 10mm. > Other heights are also possible in case of SEARAY series, but one must > order large number of them Greg FMC per VITA 57.1 standard is 8.5 mm stacking height or 10 mm stacking height (see section 3.4). You can get the SEARAY connectors (of which FMC compliant connectors are a subset) in a variety of other stacking heights too. At the end of the day, I really think that something simple and straightforward like pin headers is going to work well and will save us a lot of hassle in finding specialized connectors/worrying about longevity/connector availability/etc. > -Original Message- > From: ARTIQ [mailto:artiq-boun...@lists.m-labs.hk] On Behalf Of > Slichter, Daniel H. (Fed) > Sent: Tuesday, March 29, 2016 10:39 PM > To: Robert Jördens > Cc: Grzegorz Kasprowicz ; > artiq@lists.m-labs.hk > Subject: Re: [ARTIQ] FW: initial specification of the project > > Let me make clear that I don't have any specific opposition to FMC for > the power/digital signals. The only reason for considering other > types of connectors would be either if the desired stackup height is > not doable (this is unlikely -- one .224" bullet e.g. corning > A1A1-0001-02, plus two male connetors with .051" reference plane > distance, e.g. Molex 74315-3312, gives a total SMP height of 8.28 mm, > which works perfectly with the standard FMC stackup height of 8.5 mm > board to board), or if there is not enough real estate on the board to > meet the physical footprint requirements (FMC is larger than the QSE > connectors I sent along, for example). > > > -Original Message- > > From: Robert Jördens [mailto:r...@m-labs.hk] > > Sent: Tuesday, March 29, 2016 11:08 AM > > To: Slichter, Daniel H. (Fed) > > Cc: Sébastien Bourdeauducq ; Grzegorz Kasprowicz > > ; artiq@lists.m-labs.hk > > Subject: Re: [ARTIQ] FW: initial specification of the project > > > > On Tue, Mar 29, 2016 at 5:16 PM, Slichter, Daniel H. (Fed) > > wrote: > > > Yes, FMC could work but it's overkill in terms of pin count; one > > > might be > > able to find a smaller footprint connector with fewer pins, which > > would be advantageous. Frankly something as dumb and cheap as 2 mm > > pin headers would do the job. > > > > Yes. A pin header would be dumb if there are better suggestions. > > LPC FMC with 64 single ended signals is definitely not overkill if > > 40 signals is the estimated need. The grounding is unlikely to hurt. > > There are certainly many other offers. But if there is such a strong > > opposition to FMC, I would look for something where we can at least > > expect a long term availability that is similar to the FMC usage lifespan. > ___ > ARTIQ mailing list > https://ssl.serverraum.org/lists/listinfo/artiq ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
Re: [ARTIQ] FW: initial specification of the project
For slow control signals and supplies one can use standard 2.54 golpins and headers. I saw such solution in the RF group at the university. They pass RF using dedicated board to board coaxial connectors, rest is transmitted over standard pin headers. Greg -Original Message- From: ARTIQ [mailto:artiq-boun...@lists.m-labs.hk] On Behalf Of Slichter, Daniel H. (Fed) Sent: Monday, March 28, 2016 5:25 PM To: Sébastien Bourdeauducq Cc: Grzegorz Kasprowicz ; artiq@lists.m-labs.hk Subject: Re: [ARTIQ] FW: initial specification of the project The beauty of SMP connectors is that they are explicitly designed for board-to-board applications with substantial tolerance for misalignment. Each board has a male SMP connector, with a female-female "bullet" in between. These connectors, with the bullet in between, can tolerate substantial axial and radial misalignment (in excess of .010" - basically considerably larger than the fabrication tolerances of typical PCBs and PCB assembly) without degrading RF performance. Then one would have one multipin connector for power and digital signals that fixes the board-to-board alignment, and the SMP connectors can absorb the slack as necessary based on fabrication/assembly tolerances for their placement. I agree that if we can get suitable performance out of an FMC or other single-connector solution, that would be better from a physical simplicity standpoint. We need to test this. I may try putting together a board to do so in the near term. > -Original Message- > From: Sébastien Bourdeauducq [mailto:s...@m-labs.hk] > Sent: Saturday, March 26, 2016 10:19 AM > To: Slichter, Daniel H. (Fed) > Cc: Grzegorz Kasprowicz ; > artiq@lists.m-labs.hk > Subject: Re: [ARTIQ] FW: initial specification of the project > > On Saturday, 26 March 2016 4:06:17 PM HKT Slichter, Daniel H. (Fed) wrote: > > The cost savings from using FMC, which might amount to $50 per AMC, > > are not worth if the crosstalk will make the cards not useful for > > researchers. > > It's not only about cost of the connector - the RF daughter cards will > often need some digital signals (e.g. SPI) for control. FMC provides > plenty of pins for that. Mixing two different types of board-to-board > connectors will cause mechanical problems and I think we should not do > that. If two types of connectors are needed, one of them should use cables. > > Sébastien ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
Re: [ARTIQ] ARTIQ 1.0rc1
ARTIQ team, I noticed that the ARTIQ 1.0 release candidate is no longer in sync with the commits on the github release branch when installing through the conda main channel. Conda currently downloads commit id 1c9b8a1 from 10 days ago. Should we be pulling the latest code from git for testing of release candidate or is this behavior unintentional? Regards, Aaron On Sun, Mar 20, 2016 at 10:08 PM Sébastien Bourdeauducq wrote: > On Sunday, 20 March 2016 5:10:29 PM HKT Robert Jördens wrote: > > Users should consider switching from the nameless automatically > > generated packages for continuous integration testing in the conda > > "dev" label to the "main" label where releases and release candidates > > will be available. > > Quick note: if you've been using the development versions, and you want to > switch to releases, make sure that you disable/remove the dev channel from > your conda settings. > > Sébastien > > > ___ > ARTIQ mailing list > https://ssl.serverraum.org/lists/listinfo/artiq > ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
Re: [ARTIQ] FW: initial specification of the project
> FMC has mounting height of 8 or 10mm. > Other heights are also possible in case of SEARAY series, but one must order > large number of them Greg FMC per VITA 57.1 standard is 8.5 mm stacking height or 10 mm stacking height (see section 3.4). You can get the SEARAY connectors (of which FMC compliant connectors are a subset) in a variety of other stacking heights too. At the end of the day, I really think that something simple and straightforward like pin headers is going to work well and will save us a lot of hassle in finding specialized connectors/worrying about longevity/connector availability/etc. > -Original Message- > From: ARTIQ [mailto:artiq-boun...@lists.m-labs.hk] On Behalf Of Slichter, > Daniel H. (Fed) > Sent: Tuesday, March 29, 2016 10:39 PM > To: Robert Jördens > Cc: Grzegorz Kasprowicz ; artiq@lists.m-labs.hk > Subject: Re: [ARTIQ] FW: initial specification of the project > > Let me make clear that I don't have any specific opposition to FMC for the > power/digital signals. The only reason for considering other types of > connectors would be either if the desired stackup height is not doable (this > is > unlikely -- one .224" bullet e.g. corning A1A1-0001-02, plus two male > connetors with .051" reference plane distance, e.g. Molex 74315-3312, gives > a total SMP height of 8.28 mm, which works perfectly with the standard FMC > stackup height of 8.5 mm board to board), or if there is not enough real > estate on the board to meet the physical footprint requirements (FMC is > larger than the QSE connectors I sent along, for example). > > > -Original Message- > > From: Robert Jördens [mailto:r...@m-labs.hk] > > Sent: Tuesday, March 29, 2016 11:08 AM > > To: Slichter, Daniel H. (Fed) > > Cc: Sébastien Bourdeauducq ; Grzegorz Kasprowicz > > ; artiq@lists.m-labs.hk > > Subject: Re: [ARTIQ] FW: initial specification of the project > > > > On Tue, Mar 29, 2016 at 5:16 PM, Slichter, Daniel H. (Fed) > > wrote: > > > Yes, FMC could work but it's overkill in terms of pin count; one > > > might be > > able to find a smaller footprint connector with fewer pins, which > > would be advantageous. Frankly something as dumb and cheap as 2 mm > > pin headers would do the job. > > > > Yes. A pin header would be dumb if there are better suggestions. > > LPC FMC with 64 single ended signals is definitely not overkill if 40 > > signals is the estimated need. The grounding is unlikely to hurt. > > There are certainly many other offers. But if there is such a strong > > opposition to FMC, I would look for something where we can at least > > expect a long term availability that is similar to the FMC usage lifespan. > ___ > ARTIQ mailing list > https://ssl.serverraum.org/lists/listinfo/artiq ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
Re: [ARTIQ] FW: initial specification of the project
> There are FMC-type connectors with much smaller number of pins (SEARAY > series) Greg Sure. I think Robert wants to use the particular ones that are in the VITA FMC standard, for longevity purposes. I happen think that pin headers are the cockroaches of board-to-board connectors; they will still be around after the nuclear holocaust wipes everything else out. > -Original Message- > From: ARTIQ [mailto:artiq-boun...@lists.m-labs.hk] On Behalf Of Robert > Jördens > Sent: Tuesday, March 29, 2016 1:01 PM > To: Sébastien Bourdeauducq > Cc: Grzegorz Kasprowicz ; artiq@lists.m-labs.hk; > Slichter, Daniel H. (Fed) > Subject: Re: [ARTIQ] FW: initial specification of the project > > On Tue, Mar 29, 2016 at 11:56 AM, Sébastien Bourdeauducq > wrote: > > On Monday, 28 March 2016 6:30:52 PM HKT Slichter, Daniel H. (Fed) wrote: > >> Thus for the two examples above, using digital connectors with a 9 mm > >> or 11 mm total stackup height would give 250 um axial misalignment > >> (.010"), which is a typical tolerance one would want to use anyway with > SMP. > >> > >> More information is available in this application note: > >> > https://www.corning.com/media/worldwide/coc/documents/applications/ > mi > >> crowave > >> ApplicationNotes.pdf > > > > OK. Then mixing SMP with something else is fine IMO. > > The other connector can well be FMC. We need at least ~40 signals other > than the analog ones going to the cards. A bunch of different power supplies, > SPI control lines, identification buses, switching, attenuation settings etc. > Also since reliably reflowing SMP connectors manually to three hair widths is > rather tricky, manual assembly is of the table now anyway. And FMC give us > at least a form factor that has been tested very well. No need to reinvent the > mezzanine here. > ___ > ARTIQ mailing list > https://ssl.serverraum.org/lists/listinfo/artiq ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
Re: [ARTIQ] FW: initial specification of the project
Let me make clear that I don't have any specific opposition to FMC for the power/digital signals. The only reason for considering other types of connectors would be either if the desired stackup height is not doable (this is unlikely -- one .224" bullet e.g. corning A1A1-0001-02, plus two male connetors with .051" reference plane distance, e.g. Molex 74315-3312, gives a total SMP height of 8.28 mm, which works perfectly with the standard FMC stackup height of 8.5 mm board to board), or if there is not enough real estate on the board to meet the physical footprint requirements (FMC is larger than the QSE connectors I sent along, for example). > -Original Message- > From: Robert Jördens [mailto:r...@m-labs.hk] > Sent: Tuesday, March 29, 2016 11:08 AM > To: Slichter, Daniel H. (Fed) > Cc: Sébastien Bourdeauducq ; Grzegorz Kasprowicz > ; artiq@lists.m-labs.hk > Subject: Re: [ARTIQ] FW: initial specification of the project > > On Tue, Mar 29, 2016 at 5:16 PM, Slichter, Daniel H. (Fed) > wrote: > > Yes, FMC could work but it's overkill in terms of pin count; one might be > able to find a smaller footprint connector with fewer pins, which would be > advantageous. Frankly something as dumb and cheap as 2 mm pin headers > would do the job. > > Yes. A pin header would be dumb if there are better suggestions. > LPC FMC with 64 single ended signals is definitely not overkill if 40 signals > is > the estimated need. The grounding is unlikely to hurt. > There are certainly many other offers. But if there is such a strong > opposition > to FMC, I would look for something where we can at least expect a long term > availability that is similar to the FMC usage lifespan. ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
Re: [ARTIQ] FW: initial specification of the project
On Tue, Mar 29, 2016 at 5:16 PM, Slichter, Daniel H. (Fed) wrote: > Yes, FMC could work but it's overkill in terms of pin count; one might be > able to find a smaller footprint connector with fewer pins, which would be > advantageous. Frankly something as dumb and cheap as 2 mm pin headers would > do the job. Yes. A pin header would be dumb if there are better suggestions. LPC FMC with 64 single ended signals is definitely not overkill if 40 signals is the estimated need. The grounding is unlikely to hurt. There are certainly many other offers. But if there is such a strong opposition to FMC, I would look for something where we can at least expect a long term availability that is similar to the FMC usage lifespan. ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
Re: [ARTIQ] FW: initial specification of the project
How about something like this for board-to-board connector for power/digital? Allows 11 mm stackup, can do 40 pins in relatively small footprint, well-engineered mezzanine connector: https://www.samtec.com/products/qse There are of course many more options than just this, but just to show the alternatives to FMC. ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
Re: [ARTIQ] FW: initial specification of the project
> > OK. Then mixing SMP with something else is fine IMO. > > The other connector can well be FMC. We need at least ~40 signals other > than the analog ones going to the cards. A bunch of different power supplies, > SPI control lines, identification buses, switching, attenuation settings etc. > Also since reliably reflowing SMP connectors manually to three hair widths is > rather tricky, manual assembly is of the table now anyway. And FMC give us > at least a form factor that has been tested very well. No need to reinvent the > mezzanine here. Yes, FMC could work but it's overkill in terms of pin count; one might be able to find a smaller footprint connector with fewer pins, which would be advantageous. Frankly something as dumb and cheap as 2 mm pin headers would do the job. Manual assembly was never really one of the major concerns with these daughtercards, as many of the desired components are leadless or QFN packages with center ground pads, which are tricky for manual assembly anyway, especially if one cares about microwave performance. However, many SMP connectors have a through hole design (see below for an example from Corning Gilbert, or from Molex at http://www.molex.com/pdm_docs/sd/734153320_sd.pdf ), so it's entirely possible to achieve the kind of lateral alignment tolerances required with manual assembly. Cost-wise, the molex part quoted is less than $3 apiece on digikey at qty 750 (and $5 at qty 1), so it’s not like these connectors will be a major cost driver on the cards either. [cid:image001.png@01D1899A.9C6CA5F0] ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
Re: [ARTIQ] FW: initial specification of the project
> If 65 dB between neighboring channels is the requirement, then > comprehensive board level shielding appears to be required. Yes, this will be necessary. See my previous emails. ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
Re: [ARTIQ] FW: initial specification of the project
On Tue, Mar 29, 2016 at 11:56 AM, Sébastien Bourdeauducq wrote: > On Monday, 28 March 2016 6:30:52 PM HKT Slichter, Daniel H. (Fed) wrote: >> Thus for the two examples above, using digital connectors with a 9 mm or 11 >> mm total stackup height would give 250 um axial misalignment (.010"), which >> is a typical tolerance one would want to use anyway with SMP. >> >> More information is available in this application note: >> https://www.corning.com/media/worldwide/coc/documents/applications/microwave >> ApplicationNotes.pdf > > OK. Then mixing SMP with something else is fine IMO. The other connector can well be FMC. We need at least ~40 signals other than the analog ones going to the cards. A bunch of different power supplies, SPI control lines, identification buses, switching, attenuation settings etc. Also since reliably reflowing SMP connectors manually to three hair widths is rather tricky, manual assembly is of the table now anyway. And FMC give us at least a form factor that has been tested very well. No need to reinvent the mezzanine here. ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
Re: [ARTIQ] FW: initial specification of the project
On Monday, 28 March 2016 6:30:52 PM HKT Slichter, Daniel H. (Fed) wrote: > Thus for the two examples above, using digital connectors with a 9 mm or 11 > mm total stackup height would give 250 um axial misalignment (.010"), which > is a typical tolerance one would want to use anyway with SMP. > > More information is available in this application note: > https://www.corning.com/media/worldwide/coc/documents/applications/microwave > ApplicationNotes.pdf OK. Then mixing SMP with something else is fine IMO. ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
Re: [ARTIQ] FW: initial specification of the project
On Mon, Mar 28, 2016 at 9:14 PM, Slichter, Daniel H. (Fed) wrote: > http://suddendocs.samtec.com/testreports/hsc-report-seam-seaf-07mm_web.pdf > > There is too much crosstalk in FMC connectors (~40-65 dB typical @ 3 GHz) for > us to use them for the RF/analog daughterboards. Recommend dedicated RF > connectors (typical crosstalk better than 80 dB) for analog signal > transmission. If 65 dB between neighboring channels is the requirement, then comprehensive board level shielding appears to be required. ___ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
