Re: [time-nuts] HP 5065A repair...
That's great. Another old HP box brought back to life.
-pete
On Sun, Jul 30, 2017 at 4:24 PM, paul swed wrote:
> Ulf very good and great to hear. I did look at the clock motor driver and I
> believe you can use a ttl flip flop to drive the two transistors just fine.
> I think the ttl will run on the 4.2 V. But the transistor drive
> requirements look reasonable.
> So if you want the click click you can have it.
> Regards
> Paul
> Wb8tsl
>
>
>
> On Sun, Jul 30, 2017 at 6:28 PM, Ulf Kylenfall via time-nuts <
> time-nuts@febo.com> wrote:
>
> > After having salvaged an old 5065A that was
> > decomissioned in 1987 due to Rubidium cavity
> > heater short circuit, I have now, several
> > weeks later eventually managed to what I think
> > repair it.
> > Using a GPS-Diciplined HP105A
> > as oscilloscope trigger, the 5MHz O/P is
> > absolutely still. "Continous Operation"is ON, and the values indicated on
> > thepanel meter are almost matching thosewritten on the operating chart
> back
> > in 1987.
> >
> > The next step is to take the 5065 to my work
> > where we have two H-masers. Then it will be possible
> > to see if it meets the old specification.
> >
> > A BIG Thank You
> > to Corby Dawson!for valuable help and also to people providing
> > the documents found on KO4BB site ("First Aid...")
> > Ulf KylenfallSM6GXV
> > ___
> > time-nuts mailing list -- time-nuts@febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/
> > mailman/listinfo/time-nuts
> > and follow the instructions there.
> >
> ___
> time-nuts mailing list -- time-nuts@febo.com
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> mailman/listinfo/time-nuts
> and follow the instructions there.
>
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[time-nuts] Trimble Thunderbolt no longer determines the correct date
That does not appear to be the case. If it did a reset the DAC should have gone to the InitV eeprom setting of 2.800V, but instead mine spiked to 0.308V which is not close to the InitV or the last known DAC values. My log file shows the unit did a filter-reinit followed two seconds later by phase locking the PPS. -- > Or maybe the TBolt reset on rollover and went back to a previously saved DAC > value. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 5065A repair...
Ulf very good and great to hear. I did look at the clock motor driver and I
believe you can use a ttl flip flop to drive the two transistors just fine.
I think the ttl will run on the 4.2 V. But the transistor drive
requirements look reasonable.
So if you want the click click you can have it.
Regards
Paul
Wb8tsl
On Sun, Jul 30, 2017 at 6:28 PM, Ulf Kylenfall via time-nuts <
time-nuts@febo.com> wrote:
> After having salvaged an old 5065A that was
> decomissioned in 1987 due to Rubidium cavity
> heater short circuit, I have now, several
> weeks later eventually managed to what I think
> repair it.
> Using a GPS-Diciplined HP105A
> as oscilloscope trigger, the 5MHz O/P is
> absolutely still. "Continous Operation"is ON, and the values indicated on
> thepanel meter are almost matching thosewritten on the operating chart back
> in 1987.
>
> The next step is to take the 5065 to my work
> where we have two H-masers. Then it will be possible
> to see if it meets the old specification.
>
> A BIG Thank You
> to Corby Dawson!for valuable help and also to people providing
> the documents found on KO4BB site ("First Aid...")
> Ulf KylenfallSM6GXV
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> and follow the instructions there.
>
___
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Re: [time-nuts] Interfacing of 74ALVC divider chain to ADF4350 output (yet another low jitter sine-to-logic thread ; ) )
Use an LTC6957 the CMOS output of which has its PN specified at frequencies up to 300MHz. Virtually any discrete circuit replacement with similar performance will require a higher voltage and dissipate more power. Bruce > > On 31 July 2017 at 09:25 Attila Kinali wrote: > > On Sun, 30 Jul 2017 23:52:50 +0300 > Yuri Ostry wrote: > > > > > > But interfacing of 74ALVC flip-flop input to a ADF output in a > > 160-260 MHz > > range is not so easy question for me, especially taking low jitter > > requirements into account. Maybe someone can share tested working > > solution that > > will not add too much noise and will be more or less stable with > > temperature variations? > > > > > > CMOS signals get a bit iffy when going over 100MHz. You will probably > have to build your own board for the divider. I don't think it would > be reliable without it. As for interfacing the ADF4350 output, you will > need to use the differential output to cross the board-to-board gap. > On the divider board use a differential pair to convert the signal > to proper CMOS levels. You can use the one in the TADD2 or TICC > as an example how to do it. Make sure the f_t of the transistors > is high enough and that you give them enough current to work with. > Keep all wires on the divider board short and remove all planes > underneath the circuit, safe for the (closed) ground plane on the > bottom layer, in order to minimize stray capacitance. > > Alternatively, use something like an SY89874 as first divider > stage to get down to a more managable frequency range, then > continue with your ALVC dividers. > > Attila Kinali > > -- > You know, the very powerful and the very stupid have one thing in common. > They don't alters their views to fit the facts, they alter the facts to > fit the views, which can be uncomfortable if you happen to be one of the > facts that needs altering. -- The Doctor > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] A look inside the DS3231
Lower drain means a smaller battery or backup source... and in today's world of electronics smaller is better. But, past a certain point, it all boils down to a "spec waving" contest ;-) > What's the motivation for this, other than "because we can"? Aren't existing RTC chips capable of running 10+ years from a lithium coin cell already, to the point where the cell's self-discharge is the limiting factor? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] HP 5065A repair...
After having salvaged an old 5065A that was
decomissioned in 1987 due to Rubidium cavity
heater short circuit, I have now, several
weeks later eventually managed to what I think
repair it.
Using a GPS-Diciplined HP105A
as oscilloscope trigger, the 5MHz O/P is
absolutely still. "Continous Operation"is ON, and the values indicated on
thepanel meter are almost matching thosewritten on the operating chart back in
1987.
The next step is to take the 5065 to my work
where we have two H-masers. Then it will be possible
to see if it meets the old specification.
A BIG Thank You
to Corby Dawson!for valuable help and also to people providing
the documents found on KO4BB site ("First Aid...")
Ulf KylenfallSM6GXV
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Re: [time-nuts] Interfacing of 74ALVC divider chain to ADF4350 output (yet another low jitter sine-to-logic thread ; ) )
Hello, Thank you for your reply! Monday, July 31, 2017, 0:25:19, Attila Kinali wrote: A> Alternatively, use something like an SY89874 as first divider A> stage to get down to a more managable frequency range, then A> continue with your ALVC dividers. I think it will be easier (faster and cheaper) to get ADF4351 chip and replace it on that board, getting two more divider stages inside synth chip. Pinout is the same, if memory serve me correctly. AD is easier to get here compared to exotic Micrel clock buffer. Looks like there will be no such "quick and dirty" way with 4350. -- Best regards, Yuri mailto:y...@ostry.ru ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Interfacing of 74ALVC divider chain to ADF4350 output (yet another low jitter sine-to-logic thread ; ) )
On Sun, 30 Jul 2017 23:52:50 +0300 Yuri Ostry wrote: > But interfacing of 74ALVC flip-flop input to a ADF output in a 160-260 MHz > range is not so easy question for me, especially taking low jitter > requirements into account. Maybe someone can share tested working solution > that > will not add too much noise and will be more or less stable with > temperature variations? CMOS signals get a bit iffy when going over 100MHz. You will probably have to build your own board for the divider. I don't think it would be reliable without it. As for interfacing the ADF4350 output, you will need to use the differential output to cross the board-to-board gap. On the divider board use a differential pair to convert the signal to proper CMOS levels. You can use the one in the TADD2 or TICC as an example how to do it. Make sure the f_t of the transistors is high enough and that you give them enough current to work with. Keep all wires on the divider board short and remove all planes underneath the circuit, safe for the (closed) ground plane on the bottom layer, in order to minimize stray capacitance. Alternatively, use something like an SY89874 as first divider stage to get down to a more managable frequency range, then continue with your ALVC dividers. Attila Kinali -- You know, the very powerful and the very stupid have one thing in common. They don't alters their views to fit the facts, they alter the facts to fit the views, which can be uncomfortable if you happen to be one of the facts that needs altering. -- The Doctor ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Interfacing of 74ALVC divider chain to ADF4350 output (yet another low jitter sine-to-logic thread ; ) )
Hello, Trying to make low-PN fine tuning step synth for experiments in HF range from the parts I have on hand. Looks like the best I can do is to add extra dividers to chinese ADF4350 board from eBay that was used in the past and now is collecting dust on the shelf. But interfacing of 74ALVC flip-flop input to a ADF output in a 160-260 MHz range is not so easy question for me, especially taking low jitter requirements into account. Maybe someone can share tested working solution that will not add too much noise and will be more or less stable with temperature variations? -- Sincerely, Yuri, UA3ATQ/KI7XJ mailto:y...@ostry.ru ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] A look inside the DS3231
The typical method of frequency correction is not to add or subtract capacitance across the crystal, (like an old analog engineer would do) but rather to add or subtract pulses to the stream of cycles/pulses coming out of the crystal oscillator. More the kind of correction a digital engineer would do. The long term end result is correct, but the addition and subtraction of correction pulses shows up as jitter and short term errors. As far as the need for low battery drain, everything is going for smaller, lighter, cheaper, portable, and runs off a battery. You would probably turn your nose up at a watch, whose battery did not last at least a year. Most simple watches go several years. Now put an electronic display on it, and a GPS in it and BlueTooth LE. Everything inside is under pressure to make sure the battery lasts as long as possible. I personally don't wear a watch any more. Get GPS time from my cellphone, that fits in my watch pocket of my jeans. (I finally found a use for that pocket, after wearing pants with them for 50+ years.) But, I have to charge the thing every day, every other day, at the most. What I want, is a cellphone that I only have to charge once a week, or once a month. I don't want to have to be in the battery management business. Before we exited from the pager business, we had a customer that had a published goal of a pager that would run an entire year on one "AA" primary (alkaline throw-away) battery. Imagine changing the battery once per year, on New Years day. We were up to running for nine months from a single AA battery. Now, that was a radio receiver and a 'beeper' (and an internal clock for management purposes.). And we had a road map to get to the full year, but the cellphone systems killed the pager business first. It was all about timing, and putting as much of the IC to sleep at any given time, as you could. On Sun, Jul 30, 2017 at 8:37 AM, Mark Sims wrote: > A friend of mine is an engineer for one of the biggest manufacturers of > clock chips and has worked quite a bit on their clock chips and is quite > familiar with the issues of building consistent ultra low power oscillators > in a production product. Getting nanowatt (and now sub-nanowatt) level > oscillators to do their thing consistently is not easy. Getting them to > do it with customer supplied crystals is a big thing. Variations by the > crystal maker regularly cause previously working products to stop working. > Also they are notoriously sensitive to PCB layout issues. Older, higher > power clock chips don't have nearly as many problems as the newer ultra low > power designs. Competition to see who can make the lowest power clock > chips seems to be one of the biggest drivers for new clock chip designs. > > Oh, and although the clock chip oscillators have good long term accuracy > they tend to have lots of jitter and poor ADEVs. > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] A look inside the DS3231
On Sun, Jul 30, 2017, at 03:37 PM, Mark Sims wrote: > A friend of mine is an engineer for one of the biggest manufacturers of > clock chips and has worked quite a bit on their clock chips and is quite > familiar with the issues of building consistent ultra low power > oscillators in a production product. Getting nanowatt (and now > sub-nanowatt) level oscillators to do their thing consistently is not > easy. Getting them to do it with customer supplied crystals is a big > thing. Variations by the crystal maker regularly cause previously > working products to stop working. Also they are notoriously sensitive to > PCB layout issues. Older, higher power clock chips don't have nearly as > many problems as the newer ultra low power designs. Competition to see > who can make the lowest power clock chips seems to be one of the biggest > drivers for new clock chip designs. What's the motivation for this, other than "because we can"? Aren't existing RTC chips capable of running 10+ years from a lithium coin cell already, to the point where the cell's self-discharge is the limiting factor? Is there some application where exceptionally low power use for a clock chip would be of interest? I ask as an interested amateur not familiar with the subtleties of such designs. Cheers! -Pete ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] A look inside the DS3231
A friend of mine is an engineer for one of the biggest manufacturers of clock chips and has worked quite a bit on their clock chips and is quite familiar with the issues of building consistent ultra low power oscillators in a production product. Getting nanowatt (and now sub-nanowatt) level oscillators to do their thing consistently is not easy. Getting them to do it with customer supplied crystals is a big thing. Variations by the crystal maker regularly cause previously working products to stop working. Also they are notoriously sensitive to PCB layout issues. Older, higher power clock chips don't have nearly as many problems as the newer ultra low power designs. Competition to see who can make the lowest power clock chips seems to be one of the biggest drivers for new clock chip designs. Oh, and although the clock chip oscillators have good long term accuracy they tend to have lots of jitter and poor ADEVs. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] A look inside the DS3231
On Sun, 30 Jul 2017 08:53:51 -0500 Didier Juges wrote: > I believe I have read an app note some time ago, it may have been from > Maxim describing a kind of ring oscillator being used as a temperature > sensor which drew much less power than a bandgap or a PN junction and > directly produced a digital output Right. I always forget that there are these "digital" sensors that are much less power hungry than the "analog" ones. Attila Kinali -- You know, the very powerful and the very stupid have one thing in common. They don't alters their views to fit the facts, they alter the facts to fit the views, which can be uncomfortable if you happen to be one of the facts that needs altering. -- The Doctor ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Trimble Thunderbolt no longer determines the correct date
Unfortunately I did not have the log activated. Although I did not see a phase shift I think that that may be just luck as looking back at the screen print of tboltmon 1 sec after the roll, I see that the DAC voltage changed by +0,00533mV from the value 10mins prior to the roll. My antenna is not positioned optimally so I am used to seeing occasional 40-200ns phase offsets due to multi path. My phase shift before rollover (-9min) was -118ns and drifting toward 0. The Tbolt and only been powered on 4Hrs prior to rollover but was in position hold and had a good almanac. At rollover +1s it was 50,52ns and at 41secs after rollover the offset was 127,66ns so I didn’t think it unusual. Looking at it again, I see that the 10MHz frequency offset was 0,10ppb prior to the rollover , but 2.01ppb at +1s , so it looks like I did get a glitch, but one of lesser magnitude than you reported. > Le 30 juil. 2017 à 16:18, Tom Van Baak a écrit : > > Hi Mike, > >> I was running Tboltmon as the rollover occurred and did not see any phase >> shift. > > I'm pleased you saw no phase shift at all. Did you happen to have a TBoltmon > log running? > >> Maybe your phase offset was due to your Tbolt being in survey mode and its >> apparent position shifted . > > The particular TBolt I used for the screen capture was powered up too soon > before GPS midnight for the survey to complete. So I just entered the > coordinates manually before the photo-op. > > But if you look at the two images again, the phase shift may be due to a > change in DAC value. My theory at this point is that the DAC voltage > calculation includes at least one component based on slope; and slope implies > elapsed time interval. A calculation like that would be upset if the > underlying time frame changes by -1023 weeks instead of +1 week, or -7168 > days instead of +1 day, etc. Or maybe the TBolt reset on rollover and went > back to a previously saved DAC value. I don't know. But for those of you > making your own GPSDO, keep subtle details like this in mind. > > The duration of the recovery depends on the time constant. Notice that Mark > uses a 500 s time constant and I used the default (100 s), so my TBolt > recovered much quicker than his. I'll have more info as I sift through > several TBolt's. > > /tvb > > > - Original Message - > From: "Mike Cook" > To: "Tom Van Baak" ; "Discussion of precise time and > frequency measurement" > Sent: Saturday, July 29, 2017 11:47 PM > Subject: Re: [time-nuts] Trimble Thunderbolt no longer determines the correct > date > > > Hi, > I was running Tboltmon as the rollover occurred and did not see any phase > shift. Old type Tbolt firmware 3.0 > Maybe your phase offset was due to your Tbolt being in survey mode and its > apparent position shifted . > > Mike > > >> Le 30 juil. 2017 à 02:16, Tom Van Baak a écrit : >> >> Caught it. Some Trimble Thunderbolt TBoltmon.exe screen shots attached: >> >> GPS WN 1959 TOW 604799 (July 29, 2017 23:59:41) advanced to >> GPS WN 936 TOW 0 (December 13, 1997) instead of >> GPS WN 1960 TOW 0 (July 29, 2017 23:59:42). >> >> 1960 - 936 is 1024 weeks, as advertised for this version of the TBolt GPSDO. >> Note this happened at 23:59:42 UTC as expected (that's GPS midnight - 18 UTC >> leap seconds). I did not expect the reported 2.75 us 1PPS phase change and >> will look into that. >> >> /tvb >> > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. "The power of accurate observation is commonly called cynicism by those who have not got it. » George Bernard Shaw ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] time-nuts Digest, Vol 156, Issue 30
Chris, I have one NTP GPS based server running locally but I wanted to also setup the Mac with the Thunderbolt as a second NTP server. This way instead of using an external NTP server as a backup I would have a second local server. The Mac is Unix based and has a built in NTP server but it is normally disabled. If I enable the server isn’t it going to pull its time from the system clock ? This is the only reason I care about the system clock. Maybe I am approaching this incorrectly. Maybe the question should be how to get a local NTP server to use LH/Thunderbolt ? > > From: Chris Albertson > Subject: Re: [time-nuts] Local System Time Sync > Date: July 26, 2017 at 0:23:15 EDT > To: Lee - N2LEE , Discussion of precise time and frequency > measurement > > > You should be using NTP for that. > > Simply "syncing" the local clock to GPS is never the best thing to do. If > you think about it 50% of the time the local clock would have to go > backwards and 50% forwards. This means you could have the system time be > at the same time twice or you have missing time intervals. > > The correct way is to adjust the RATE of the local clock so you never have > missing or double time. This is exactly the same as building a GPSDO. > Every adjustment period you compare there PHASE of the local clock to GPS > then adjust the RATE if required. NTP does this. > > On Tue, Jul 25, 2017 at 7:45 PM, Lee - N2LEE via time-nuts < > time-nuts@febo.com> wrote: > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Trimble Thunderbolt no longer determines the correct date
Hi Mike, > I was running Tboltmon as the rollover occurred and did not see any phase > shift. I'm pleased you saw no phase shift at all. Did you happen to have a TBoltmon log running? > Maybe your phase offset was due to your Tbolt being in survey mode and its > apparent position shifted . The particular TBolt I used for the screen capture was powered up too soon before GPS midnight for the survey to complete. So I just entered the coordinates manually before the photo-op. But if you look at the two images again, the phase shift may be due to a change in DAC value. My theory at this point is that the DAC voltage calculation includes at least one component based on slope; and slope implies elapsed time interval. A calculation like that would be upset if the underlying time frame changes by -1023 weeks instead of +1 week, or -7168 days instead of +1 day, etc. Or maybe the TBolt reset on rollover and went back to a previously saved DAC value. I don't know. But for those of you making your own GPSDO, keep subtle details like this in mind. The duration of the recovery depends on the time constant. Notice that Mark uses a 500 s time constant and I used the default (100 s), so my TBolt recovered much quicker than his. I'll have more info as I sift through several TBolt's. /tvb - Original Message - From: "Mike Cook" To: "Tom Van Baak" ; "Discussion of precise time and frequency measurement" Sent: Saturday, July 29, 2017 11:47 PM Subject: Re: [time-nuts] Trimble Thunderbolt no longer determines the correct date Hi, I was running Tboltmon as the rollover occurred and did not see any phase shift. Old type Tbolt firmware 3.0 Maybe your phase offset was due to your Tbolt being in survey mode and its apparent position shifted . Mike > Le 30 juil. 2017 à 02:16, Tom Van Baak a écrit : > > Caught it. Some Trimble Thunderbolt TBoltmon.exe screen shots attached: > > GPS WN 1959 TOW 604799 (July 29, 2017 23:59:41) advanced to > GPS WN 936 TOW 0 (December 13, 1997) instead of > GPS WN 1960 TOW 0 (July 29, 2017 23:59:42). > > 1960 - 936 is 1024 weeks, as advertised for this version of the TBolt GPSDO. > Note this happened at 23:59:42 UTC as expected (that's GPS midnight - 18 UTC > leap seconds). I did not expect the reported 2.75 us 1PPS phase change and > will look into that. > > /tvb > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] A look inside the DS3231
That device also has analog circuitry for the oscillator itself and the temperature sensor and the temperature compensation. I believe I have read an app note some time ago, it may have been from Maxim describing a kind of ring oscillator being used as a temperature sensor which drew much less power than a bandgap or a PN junction and directly produced a digital output. The DAC itself, or whatever circuit they use for temp compensation also has analog components and must use pico power. Quite amazing. On Jul 30, 2017 7:13 AM, "Attila Kinali" wrote: > On Sun, 30 Jul 2017 12:23:17 +0200 > Pete Stephenson wrote: > > > > > - I find it remarkable that this circuit can operate on less than a > > > > microamp during normal usage, including temperature conversion. > > > > > > That's not so remarkable. If you make the transistors long, then > > > you get very low leakage. Couple that with small clock frequency > > > and you use very little current. Modern ICs only use so much current > > > because they have so many transistors, which are also optimized > > > for being fast, rather then low leakage. > > > > Good point! I admit the details of optimizing transistors for different > > purposes is beyond my ken, and I appreciate the insight. > > > There are multiple optimization points. One is to select a prodcution > process that is optimized for low leakage. I.e. thick gate oxide > and high threshold voltage. Both of these parameters imply higher > suplly voltage. > Then, in the design, you make your transistors long and large. > > The problem here is, that power consumption scales proportional > to the square of supply voltage, the gate capacitance and the > switching frequency. This means, if you choose a low leakage > process, and thus high supply voltage, your power consumtion > will go up. The same goes for choosing large transistors. > Hence it becomes a trade-off between static (leakage) and > dynamic (through gate capacitance) power consumption. > > > > > > The DS3231 has on-board temperature monitoring to correct the crystal > > > > frequency: is this something where they would have bothered putting a > > > > separate sensor next to the crystal itself, or are the die and the > > > > crystal are close enough and in the same package that they could use > an > > > > on-die sensor like a diode and call that "good enough"? > > > > > > My guess would be that it's a PN-junction or a bandgap temperature > > > sensor somewhere on the chip. Adding another part increases the cost > > > of production quite considerably. > > > > Indeed. At first glance, I was surprised not to see tiny discrete > > capacitors within the chip package itself, as I assumed (incorrectly) > > that getting sufficient capacitance to steer a crystal a little would > > require larger capacitors than could be easily put on a die, but then I > > remembered that each LSB in the aging register only changes the > > frequency by 0.1ppm at 25C, so that wouldn't need a large amount of > > capacitance. > > As a rule of thumb, you can assume that in an "old" (aka large node size) > process the gate capacitance is approximately 1nF per mm^2. So, you can > build quite easily 10-100pF of capacitors on-chip. > > > Attila Kinali > -- > You know, the very powerful and the very stupid have one thing in common. > They don't alters their views to fit the facts, they alter the facts to > fit the views, which can be uncomfortable if you happen to be one of the > facts that needs altering. -- The Doctor > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Low-power oscillators (was: A look inside the DS3231)
On Sun, 30 Jul 2017 08:15:57 -0400 Tim Shoppa wrote: > I would imagine there's a series of patents by watch > companies on this subject as well probably all back in the 1970's and There are also a lot of papers and books. I can recommend those written by Eric Vittoz, who was the mastermind behind quite a few of the oscillator circuits of the Swiss watch industry. In particular his book on low power oscillators[1]. He also wrote a review of the history of low power electronics in the watch industry about 10 years ago[2], which is also very much worth a read. Attila Kinali [1] "Low-Power Crystal and MEMS Oscillators", by Eric Vittoz, 2010 [2] "The Electronic Watch and Low-Power Circuits", by Eric Vittoz, 2008 https://doi.org/10.1109/N-SSC.2008.4785777 -- You know, the very powerful and the very stupid have one thing in common. They don't alters their views to fit the facts, they alter the facts to fit the views, which can be uncomfortable if you happen to be one of the facts that needs altering. -- The Doctor ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] A look inside the DS3231
On the subject of low-current 32kHz oscillators:
DS3231 spec says typical 1uA for timekeeping and circa 600uA for
temperature conversion. I understand they periodicailly kick the
temperature conversion on but only for extremely short duty cycles and this
is included in the 1uA.
Standard DS12887 spec was 500nA with the oscillator and counter logic
running. This did not have any temperature conversion/compensation.
RCA published a 4007-based 32kHz oscillator that was circa 1uA but I think
that spec was at 1.5V. RCA got a patent on putting a resistor in the drain
of the first stage to slow it down and reduce power consumption to get down
to 1uA. So in the DS12887, Dallas figured out how to go at least a factor
of two lower in power. I would imagine there's a series of patents by watch
companies on this subject as well probably all back in the 1970's and
1980's.
Tim N3QE
On Sat, Jul 29, 2017 at 2:32 PM, Pete Stephenson wrote:
> On Thu, Jul 27, 2017, at 09:46 PM, Trent Piepho wrote:
> > Looks like it still says "DALLAS SEMICONDUCTOR" to the left of Maxim.
> > Maybe Maxim only wanted to change the mask enough to find some empty
> > space to sign it?
>
> It does indeed say "DALLAS SEMICONDUCTOR".
>
> I managed to get some high-quality photos using the microscope's
> on-board camera and have updated the photo album at
> https://imgur.com/a/0zudj with the newest ones (they're the
> all-rectangular photos below the two circular photos). There's some
> high-resolution composite images.
>
> Some things I found interesting:
> - There's a section just above the "Maxim" part that has several
> snippets of text ("17A3", "16A3", etc.). In normal light, each of these
> bits of text is a different color, where the colors correspond to
> different layers of the chip. Each bit of text has a different depth of
> focus, indicating they're physically closer or further from the lens.
> Does anyone know what material the colors might correspond to?
>
> - There's several square grids of circles-in-squares circuit elements. I
> have no idea what these are.
>
> - I find it remarkable that this circuit can operate on less than a
> microamp during normal usage, including temperature conversion.
>
> The DS3231 has on-board temperature monitoring to correct the crystal
> frequency: is this something where they would have bothered putting a
> separate sensor next to the crystal itself, or are the die and the
> crystal are close enough and in the same package that they could use an
> on-die sensor like a diode and call that "good enough"?
>
> Cheers!
> -Pete
>
> --
> Pete Stephenson
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> and follow the instructions there.
>
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Re: [time-nuts] A look inside the DS3231
On Sun, 30 Jul 2017 12:23:17 +0200 Pete Stephenson wrote: > > > - I find it remarkable that this circuit can operate on less than a > > > microamp during normal usage, including temperature conversion. > > > > That's not so remarkable. If you make the transistors long, then > > you get very low leakage. Couple that with small clock frequency > > and you use very little current. Modern ICs only use so much current > > because they have so many transistors, which are also optimized > > for being fast, rather then low leakage. > > Good point! I admit the details of optimizing transistors for different > purposes is beyond my ken, and I appreciate the insight. There are multiple optimization points. One is to select a prodcution process that is optimized for low leakage. I.e. thick gate oxide and high threshold voltage. Both of these parameters imply higher suplly voltage. Then, in the design, you make your transistors long and large. The problem here is, that power consumption scales proportional to the square of supply voltage, the gate capacitance and the switching frequency. This means, if you choose a low leakage process, and thus high supply voltage, your power consumtion will go up. The same goes for choosing large transistors. Hence it becomes a trade-off between static (leakage) and dynamic (through gate capacitance) power consumption. > > > The DS3231 has on-board temperature monitoring to correct the crystal > > > frequency: is this something where they would have bothered putting a > > > separate sensor next to the crystal itself, or are the die and the > > > crystal are close enough and in the same package that they could use an > > > on-die sensor like a diode and call that "good enough"? > > > > My guess would be that it's a PN-junction or a bandgap temperature > > sensor somewhere on the chip. Adding another part increases the cost > > of production quite considerably. > > Indeed. At first glance, I was surprised not to see tiny discrete > capacitors within the chip package itself, as I assumed (incorrectly) > that getting sufficient capacitance to steer a crystal a little would > require larger capacitors than could be easily put on a die, but then I > remembered that each LSB in the aging register only changes the > frequency by 0.1ppm at 25C, so that wouldn't need a large amount of > capacitance. As a rule of thumb, you can assume that in an "old" (aka large node size) process the gate capacitance is approximately 1nF per mm^2. So, you can build quite easily 10-100pF of capacitors on-chip. Attila Kinali -- You know, the very powerful and the very stupid have one thing in common. They don't alters their views to fit the facts, they alter the facts to fit the views, which can be uncomfortable if you happen to be one of the facts that needs altering. -- The Doctor ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt rollover glitch
On Sun, Jul 30, 2017, at 04:49 AM, Mark Sims wrote: > It looks like it took three hours for the effects of the rollover glitch > to mostly settle out. > > BTW, if you only use Lady Heather with a Thunderbolt, you can force the > rollover state from the command line or heather.cfg file by using the /ro > command line option. If you do that you won't have invalid dates for the > 10-15 seconds it takes for Heather's automatic rollover corrector to kick > in. If you have /ro in the heather.cfg file and wish to temporarily > cancel it to play with another receiver that does not have a rollover > issue, you can start Heather with /ro=0 I saw a very similar glitch. Out of curiosity, have you done anything particular to keep the oscillator so stable? Mine seems a bit more noisy: if I set my display to 2ppt/div as you have, things are off the scale. I typically see a span of ~1000-1500 ppt with an RMS of ~100-200 ppt. To be fair, I'm just using an old Cisco power supply from the eBay vendor that sold me the Thunderbolt, and my Thunderbolt is sitting on a block of foam on the floor in a room at the apartment with no particular temperature control. Cheers! -Pete -- Pete Stephenson ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] A look inside the DS3231
On Sun, Jul 30, 2017, at 11:15 AM, Attila Kinali wrote: > On Sat, 29 Jul 2017 20:32:30 +0200 > Pete Stephenson wrote: > > > - There's several square grids of circles-in-squares circuit elements. I > > have no idea what these are. > > If you look closely, these are actually suqares-in-squares. > I am not sure, but my guess would be that these are the > capacitor banks for the correction of the oscillator frequency. True, the larger ones are squares-in-squares, but the smaller ones to the left look like circles-in-octagons, but I find it hard to see the details of the smaller features. Either way, I should probably stare less through microscope eyepieces. It seems to stress the eyes a bit. > > - I find it remarkable that this circuit can operate on less than a > > microamp during normal usage, including temperature conversion. > > That's not so remarkable. If you make the transistors long, then > you get very low leakage. Couple that with small clock frequency > and you use very little current. Modern ICs only use so much current > because they have so many transistors, which are also optimized > for being fast, rather then low leakage. Good point! I admit the details of optimizing transistors for different purposes is beyond my ken, and I appreciate the insight. > > The DS3231 has on-board temperature monitoring to correct the crystal > > frequency: is this something where they would have bothered putting a > > separate sensor next to the crystal itself, or are the die and the > > crystal are close enough and in the same package that they could use an > > on-die sensor like a diode and call that "good enough"? > > My guess would be that it's a PN-junction or a bandgap temperature > sensor somewhere on the chip. Adding another part increases the cost > of production quite considerably. Indeed. At first glance, I was surprised not to see tiny discrete capacitors within the chip package itself, as I assumed (incorrectly) that getting sufficient capacitance to steer a crystal a little would require larger capacitors than could be easily put on a die, but then I remembered that each LSB in the aging register only changes the frequency by 0.1ppm at 25C, so that wouldn't need a large amount of capacitance. As you say, minimizing part count keeps the price down and makes the design simpler. Cheers! -Pete -- Pete Stephenson ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] A look inside the DS3231
On Sat, 29 Jul 2017 20:32:30 +0200 Pete Stephenson wrote: > - There's several square grids of circles-in-squares circuit elements. I > have no idea what these are. If you look closely, these are actually suqares-in-squares. I am not sure, but my guess would be that these are the capacitor banks for the correction of the oscillator frequency. > - I find it remarkable that this circuit can operate on less than a > microamp during normal usage, including temperature conversion. That's not so remarkable. If you make the transistors long, then you get very low leakage. Couple that with small clock frequency and you use very little current. Modern ICs only use so much current because they have so many transistors, which are also optimized for being fast, rather then low leakage. > The DS3231 has on-board temperature monitoring to correct the crystal > frequency: is this something where they would have bothered putting a > separate sensor next to the crystal itself, or are the die and the > crystal are close enough and in the same package that they could use an > on-die sensor like a diode and call that "good enough"? My guess would be that it's a PN-junction or a bandgap temperature sensor somewhere on the chip. Adding another part increases the cost of production quite considerably. Attila Kinali -- You know, the very powerful and the very stupid have one thing in common. They don't alters their views to fit the facts, they alter the facts to fit the views, which can be uncomfortable if you happen to be one of the facts that needs altering. -- The Doctor ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
