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Andrey Sviyazov andreysviyaz at gmail.comHi Jean-Samuel. I spent a lot of time yesterday and this morning because I trying to fix DC-DC issue which I mentioned few days ago (see pics). Unfortunatelly, result seems close to zero so far. I never saw so strange problems with dc-dc converters before. I am sure that there are no problems in v1 and also that this problems because of syncro mode. Now I am trying to describe this issue, may be anybody have experience with this kind problem. Let me know if you can help me here too. Regarding +3.3V LDO regulators for LMS. Here attached pics of noise plots with LDO's and when supplied from +3.3VFPGA through TI1608U601. I can't find any significant difference there. I think we can replace LDO's by RF chokes without derating performances. In this case, power consumption decreased to 11..12W in dependance of values TXVGA. Regarding GSM spectrum requirements you mentioned. As you can see, yesterday I've measured it again when made experiments around +3.3V. I found that we didn't meet requirements only when deep saturation occur. I mean when TXVGA2 higher then 23 (i.e. 24 and 25). Best regards, Andrey Sviyazov. 2012/11/2 Jean-Samuel Najnudel - BJT PARTNERS SARL <jsn at bjtpartners.com> > Hi Andrey, > > > Thank you very muchf or your reply. > > Regarding the requirement at f +/- 400 KHz, the spec mentions our signal > must be -60 dBc bellow the signal at f. > You can get more details on the GSM 05.05 spec (part 4.2), from page 15. > http://p3e.rats.fi/oh2mqk/GSM/GSM-05.05.pdf* > * > To pass this spec, we need to get our phase noise bellow -113 dBc/Hz at > 400 KHz. > On last measurements, we either fail or just pass this spec. > If possible, this would be great to try to tune the charge pump and the > loop filter passives to get our phase noise as low as possible. > I know you already worked on this and already improved this but, if you > have some ideas to decrease a bit more the phase noise, this would be very > interesting. > > Best regards. > > Jean-Samuel. > :-) > > > > On Wed, Oct 31, 2012 at 10:19 PM, Andrey Sviyazov <andreysviyaz at gmail.com>wrote: > >> Hi Jean-Samuel. >> >> About power consumption and performancea I can say that spurs at 500 kHz >> offset around 6dB above TX LO noise plot. >> It wad measured when 3.3V come from dogs through TI2012U601. >> Tomorrow I'll measure all again and share pics in this topic. >> As I mentioned, I'll try to find better filter to suppress 500kHz. >> Please let me know any partnumbers or suppliers you known. >> Also unoccupied place under 3.3V LDO's near LMS seems a good place for >> thermal sensors. >> About rf connectors, now I am sure that MCX much better then U_FL and we >> should return them. >> To connect UmSEL to UmTRX v2.1 required U_FL-MCX cable assemblies till >> new UmSEL version. >> Also possible to use direct cable soldering to UmSEL board. >> Of course, last variant look not perfect. >> About requirements at 400kHz we can't meet, I actually can't understand >> what do you mean. >> >> >> Best regards, >> Andrey Sviyazov. >> (Sent from my mobile client) >> >> 31.10.2012 22:47 пользователь "Jean-Samuel Najnudel - BJT PARTNERS SARL" < >> jsn at bjtpartners.com> написал: >> >> Hi Andrey, >>> >>> Do you think it will be possible to decrease the power consumption and >>> to keep the best possible performances for industrial applications ? >>> I know you cannot be sure about this but I would like to know how >>> confident you feel about this ? >>> >>> Best regards. >>> >>> Jean-Samuel. >>> :-) >>> >>> >>> On Wed, Oct 31, 2012 at 7:40 PM, Andrey Sviyazov <andreysviyaz at gmail.com >>> > wrote: >>> >>>> Hi Jean-Samuel, Alexander. >>>> >>>> Tomorrow I'll let you know what possible to make on time. >>>> And we should set time limit for this. >>>> For example, next morning. >>>> >>>> Best regards, >>>> Andrey Sviyazov. >>>> (Sent from my mobile client) >>>> 31.10.2012 22:24 пользователь "Jean-Samuel Najnudel - BJT PARTNERS >>>> SARL" <jsn at bjtpartners.com> написал: >>>> >>>> Hi Alexander, >>>>> >>>>> Thank you very much for your reply. >>>>> >>>>> Why skip/populate LMS power supply block ? >>>>> As I understand we always need the LMS power supply block. I probably >>>>> missed something. Could you explain this in more details to let me better >>>>> understand ? >>>>> >>>>> Thanks a lot for your help. >>>>> >>>>> Best regards. >>>>> >>>>> Jean-Samuel. >>>>> :-) >>>>> >>>>> >>>>> On Wed, Oct 31, 2012 at 7:14 PM, Alexander Chemeris < >>>>> alexander.chemeris at gmail.com> wrote: >>>>> >>>>>> Yes, lesser input voltage range makes sense only if it saves >$10 >>>>>> and/or considerably increases power efficiency. I think this not the >>>>>> case, and then only these changes will be needed: >>>>>> >>>>>> * traditional power connector >>>>>> * MCX RF connector, because they sustain much more connect-disconnect >>>>>> cycles >>>>>> * lower power consumption mod >>>>>> >>>>>> I would appreciate if we could keep the same PCB for both versions and >>>>>> populate the proper version of power connector/RF connector and >>>>>> skip/populate LMS power supply block. >>>>>> >>>>>> On Wed, Oct 31, 2012 at 9:56 PM, Jean-Samuel Najnudel - BJT PARTNERS >>>>>> SARL <jsn at bjtpartners.com> wrote: >>>>>> > Hi Alexander, >>>>>> > >>>>>> > This would be much easier to have the same board for both lab and >>>>>> > deployment. Only the UmSEL would make the difference. >>>>>> > For deployment, I really need wide input voltage range as I plan to >>>>>> power >>>>>> > the whole system (UmTRX + PA) with a single 28V supply. >>>>>> > Even if this can save a few euros, I would really prefer we do not >>>>>> make the >>>>>> > input voltage range smaller. >>>>>> > By the way, even for lab, it might be convenient and it can avoid >>>>>> damages in >>>>>> > case of wrong voltage supply. >>>>>> > >>>>>> > Best regards. >>>>>> > >>>>>> > Jean-Samuel. >>>>>> > :-) >>>>>> > >>>>>> > >>>>>> > >>>>>> > On Wed, Oct 31, 2012 at 6:50 PM, Alexander Chemeris >>>>>> > <alexander.chemeris at gmail.com> wrote: >>>>>> >> >>>>>> >> Andrey, how much time do you need to create 2.1? If it's mire than >>>>>> a day, >>>>>> >> we should postpone this. I believe that enclosure is a much more >>>>>> important >>>>>> >> issue at this moment. >>>>>> >> >>>>>> >> I think we need following changes for the lab version: >>>>>> >> * traditional power connector >>>>>> >> * MCX RF connector, because they sustain much more >>>>>> connect-disconnect >>>>>> >> cycles >>>>>> >> * lower power consumption mod >>>>>> >> * smaller input voltage range (only if this makes things cheaper) >>>>>> >> >>>>>> >> Sent from my Android device. >>>>>> >> >>>>>> >> -- >>>>>> >> Regards, >>>>>> >> Alexander Chemeris >>>>>> >> CEO, Fairwaves LLC >>>>>> >> http://fairwaves.ru >>>>>> >> >>>>>> >> 31.10.2012 14:05 пользователь "Andrey Sviyazov" < >>>>>> andreysviyaz at gmail.com> >>>>>> >> написал: >>>>>> >> >>>>>> >>> Hi Jean-Samuel. >>>>>> >>> >>>>>> >>> First of all, you didn't said about delay duration :) >>>>>> >>> I can't delay this batch just due to my wishes that each next >>>>>> batch >>>>>> >>> should work more and more ideally. >>>>>> >>> >>>>>> >>>> These modifications looks interesting. I think it is a good idea. >>>>>> >>> >>>>>> >>> Hope so. >>>>>> >>> >>>>>> >>>> >>>>>> >>>> I just have a few question. >>>>>> >>>> >>>>>> >>>> Why do you call this board revision 2.1 "a special batch for >>>>>> labs" ? >>>>>> >>>> Would these modifications make this revision 2.1 also more >>>>>> suitable for >>>>>> >>>> field deployment, at least as much as the revision 2.0 ? >>>>>> >>> >>>>>> >>> Because of I can fix only known issues. >>>>>> >>> Also not all really required improvements are known yet. >>>>>> >>> >>>>>> >>>> Decreasing power consumption to 10..11 W would be great. Is >>>>>> there any >>>>>> >>>> drawbacks of this modification ? Would it decrease some >>>>>> performances ? If >>>>>> >>>> not, this modifiction to decrease power consumption is a >>>>>> significant very >>>>>> >>>> good modification. >>>>>> >>> >>>>>> >>> Decreasing of performances it is only spurs with DC/DC conversion >>>>>> freq >>>>>> >>> ~500kHz. >>>>>> >>> Now I searching more good LC filter to suppress it better than >>>>>> TI2012U601 >>>>>> >>> can. >>>>>> >>> >>>>>> >>>> Do you have enough space on the board to replace some U_FL >>>>>> connectors >>>>>> >>>> with MCX connectors as you suggest ? >>>>>> >>> >>>>>> >>> Yes, but may be not all should be MCX. >>>>>> >>> Of course I did not insist, but just asking whether there is a >>>>>> reason to >>>>>> >>> do it or not. >>>>>> >>> >>>>>> >>>> An external LNA would probably need around 5 Volts instead of >>>>>> 6V. A >>>>>> >>>> small PA would probably need a little bit higher voltage. Do you >>>>>> think it >>>>>> >>>> would be possible to have a variable voltage low power connector >>>>>> ? >>>>>> >>> >>>>>> >>> On my opinion, variable voltage is not good idea. >>>>>> >>> For example for LNA's better to place low noise LDO 6V to 5V near >>>>>> to IC's >>>>>> >>> to get Vcc clean too. >>>>>> >>> >>>>>> >>>> By the way, could you pelase also add the 2 LMS output matching >>>>>> >>>> capacitors we need to improve output power figures in the 1800 >>>>>> band ? >>>>>> >>> >>>>>> >>> Of course, because it is issue which should be fixed, but not >>>>>> >>> improvement. >>>>>> >>> >>>>>> >>> Best regards, >>>>>> >>> Andrey Sviyazov. >>>>>> > >>>>>> > >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> Regards, >>>>>> Alexander Chemeris. >>>>>> CEO, Fairwaves LLC / ООО УмРадио >>>>>> http://fairwaves.ru >>>>>> >>>>> >>>>> >>> > -------------- next part -------------- An HTML attachment was scrubbed... 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