Re: [time-nuts] FE-5680A Voltage?
Hi The issue is the efficiency drop off as the voltage differential goes low. The ebay boards normally don't have any heat sinking on them. The LPRO pulls full current for quite a while when it warms up. Bob On Sep 12, 2013, at 10:40 PM, Orin Eman orin.e...@gmail.com wrote: Yes, my reading of the datasheet was the same. 18V in would be fine for 15V output. My concern would be how noisy the output would be. I have 9 of the from China ebay boards here (gave one to my boss to play with). I should wire one up and take a look. At any rate, I think a turn or two of the output wires through a ferrite bead would be in order. The data sheet shows a secondary filter of 3uH/180uF as well which I'd certainly want to use to feed a 5680A. Shouldn't do any harm, might do some good. Orin. On Thu, Sep 12, 2013 at 7:19 PM, Robert LaJeunesse rlajeune...@sbcglobal.net wrote: Looking at the LM2596 datasheet the switch transistor saturation voltage is 1.5V max at 3A (1.16v typ). That and an educated guess of about 0.25V for inductor loss combine to set the minimum difference between input and output. The 1.23V reference is about +/-3% accurate, so after setting the buckboard to 15.00V out (at 25C) expect it to shift at most 0.5V over time and temp. Add that to the minimum in-out difference and now you are at a minimum safe input of 2.25V above the nominal 15V output, or 17.25V in. An old 19V 3A laptop supply might be a good supply to use for this, if you were local I'd hand you one. As for efficiency, that just tells you the amount of heat the regulator, plus inductor, plus diode, etc. will throw off. FWIW the datasheet Figure 5 indicates you should expect about 88% or better efficiency for 15V out and at least 2V higher input voltage. (Doing some switching power supply design for a living does help with my understanding of them, but not ever enough!) Bob LaJeunesse ___ 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] FE-5680A Voltage?
I decided to order a Rb standard, and I was wondering what the lower limit on the 15V power requirement is? I have a PSU that will go up to 14.25V and my next closest is 18V. Should I just get a new 15V PSU before this gets in? Maybe I can make a quick mod on the big one and take it up to 15V. Bob - AE6RV ___ 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] FE-5680A Voltage?
Hi As I recall, 15 volts is sort of the minimum they recommend on most of the variations of the 5680. The internal regulators will probably be happier with 18 volts than with 14.25. You best bet is indeed a 15 V supply. Bob On Sep 12, 2013, at 11:03 AM, Bob Stewart b...@evoria.net wrote: I decided to order a Rb standard, and I was wondering what the lower limit on the 15V power requirement is? I have a PSU that will go up to 14.25V and my next closest is 18V. Should I just get a new 15V PSU before this gets in? Maybe I can make a quick mod on the big one and take it up to 15V. Bob - AE6RV ___ 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] FE-5680A Voltage?
A good supply is desirable wall warts aren't. Enjoy your new Rb Regards Paul WB8TSL On Thu, Sep 12, 2013 at 6:01 PM, Bob Stewart b...@evoria.net wrote: Thanks Bob. I looked at the datasheet again and found that they do like 15-18. Unfortunately my 18V supply is a wallwart that supplies 22.5-18V, 2.0-2.5A. By the ordering, I assume that means it's load dependent. So, I guess I'll find some Plan B. Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, September 12, 2013 4:52 PM Subject: Re: [time-nuts] FE-5680A Voltage? Hi As I recall, 15 volts is sort of the minimum they recommend on most of the variations of the 5680. The internal regulators will probably be happier with 18 volts than with 14.25. You best bet is indeed a 15 V supply. Bob On Sep 12, 2013, at 11:03 AM, Bob Stewart b...@evoria.net wrote: I decided to order a Rb standard, and I was wondering what the lower limit on the 15V power requirement is? I have a PSU that will go up to 14.25V and my next closest is 18V. Should I just get a new 15V PSU before this gets in? Maybe I can make a quick mod on the big one and take it up to 15V. Bob - AE6RV ___ 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 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] FE-5680A Voltage?
Thanks Bob. I looked at the datasheet again and found that they do like 15-18. Unfortunately my 18V supply is a wallwart that supplies 22.5-18V, 2.0-2.5A. By the ordering, I assume that means it's load dependent. So, I guess I'll find some Plan B. Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, September 12, 2013 4:52 PM Subject: Re: [time-nuts] FE-5680A Voltage? Hi As I recall, 15 volts is sort of the minimum they recommend on most of the variations of the 5680. The internal regulators will probably be happier with 18 volts than with 14.25. You best bet is indeed a 15 V supply. Bob On Sep 12, 2013, at 11:03 AM, Bob Stewart b...@evoria.net wrote: I decided to order a Rb standard, and I was wondering what the lower limit on the 15V power requirement is? I have a PSU that will go up to 14.25V and my next closest is 18V. Should I just get a new 15V PSU before this gets in? Maybe I can make a quick mod on the big one and take it up to 15V. Bob - AE6RV ___ 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 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] FE-5680A Voltage?
Thanks Paul. I remember when I joined this group a few weeks(?) ago I was just looking for some cheap way to improve the accuracy of my counter. So I decided to build a cheap, entry level GSPDO. And I bought a 3456A because I didn't understand my code had a positive feedback loop.. And I got a 5335A. And I spent many many hours turning Bert's FLL into a PLL. And now I'm getting a Rb standard as a check for the code I'm perfecting for my GPSDO. You guys were right. This time stuff is more addictive than crack. I just tell everyone I'm building a time machine. =) Bob From: paul swed paulsw...@gmail.com To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, September 12, 2013 5:31 PM Subject: Re: [time-nuts] FE-5680A Voltage? A good supply is desirable wall warts aren't. Enjoy your new Rb Regards Paul WB8TSL On Thu, Sep 12, 2013 at 6:01 PM, Bob Stewart b...@evoria.net wrote: Thanks Bob. I looked at the datasheet again and found that they do like 15-18. Unfortunately my 18V supply is a wallwart that supplies 22.5-18V, 2.0-2.5A. By the ordering, I assume that means it's load dependent. So, I guess I'll find some Plan B. Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, September 12, 2013 4:52 PM Subject: Re: [time-nuts] FE-5680A Voltage? Hi As I recall, 15 volts is sort of the minimum they recommend on most of the variations of the 5680. The internal regulators will probably be happier with 18 volts than with 14.25. You best bet is indeed a 15 V supply. Bob On Sep 12, 2013, at 11:03 AM, Bob Stewart b...@evoria.net wrote: I decided to order a Rb standard, and I was wondering what the lower limit on the 15V power requirement is? I have a PSU that will go up to 14.25V and my next closest is 18V. Should I just get a new 15V PSU before this gets in? Maybe I can make a quick mod on the big one and take it up to 15V. Bob - AE6RV ___ 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 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] FE-5680A Voltage?
So true in all aspects. On Thu, Sep 12, 2013 at 6:43 PM, Bob Stewart b...@evoria.net wrote: Thanks Paul. I remember when I joined this group a few weeks(?) ago I was just looking for some cheap way to improve the accuracy of my counter. So I decided to build a cheap, entry level GSPDO. And I bought a 3456A because I didn't understand my code had a positive feedback loop.. And I got a 5335A. And I spent many many hours turning Bert's FLL into a PLL. And now I'm getting a Rb standard as a check for the code I'm perfecting for my GPSDO. You guys were right. This time stuff is more addictive than crack. I just tell everyone I'm building a time machine. =) Bob From: paul swed paulsw...@gmail.com To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, September 12, 2013 5:31 PM Subject: Re: [time-nuts] FE-5680A Voltage? A good supply is desirable wall warts aren't. Enjoy your new Rb Regards Paul WB8TSL On Thu, Sep 12, 2013 at 6:01 PM, Bob Stewart b...@evoria.net wrote: Thanks Bob. I looked at the datasheet again and found that they do like 15-18. Unfortunately my 18V supply is a wallwart that supplies 22.5-18V, 2.0-2.5A. By the ordering, I assume that means it's load dependent. So, I guess I'll find some Plan B. Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, September 12, 2013 4:52 PM Subject: Re: [time-nuts] FE-5680A Voltage? Hi As I recall, 15 volts is sort of the minimum they recommend on most of the variations of the 5680. The internal regulators will probably be happier with 18 volts than with 14.25. You best bet is indeed a 15 V supply. Bob On Sep 12, 2013, at 11:03 AM, Bob Stewart b...@evoria.net wrote: I decided to order a Rb standard, and I was wondering what the lower limit on the 15V power requirement is? I have a PSU that will go up to 14.25V and my next closest is 18V. Should I just get a new 15V PSU before this gets in? Maybe I can make a quick mod on the big one and take it up to 15V. Bob - AE6RV ___ 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 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 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] FE-5680A Voltage?
I just remembered: Someone here or on the Agilent list suggested I buy a handful of those LM2596 buckboards a few weeks ago. That one wallwart should have enough headroom to give me 15V. Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, September 12, 2013 4:52 PM Subject: Re: [time-nuts] FE-5680A Voltage? Hi As I recall, 15 volts is sort of the minimum they recommend on most of the variations of the 5680. The internal regulators will probably be happier with 18 volts than with 14.25. You best bet is indeed a 15 V supply. Bob On Sep 12, 2013, at 11:03 AM, Bob Stewart b...@evoria.net wrote: I decided to order a Rb standard, and I was wondering what the lower limit on the 15V power requirement is? I have a PSU that will go up to 14.25V and my next closest is 18V. Should I just get a new 15V PSU before this gets in? Maybe I can make a quick mod on the big one and take it up to 15V. Bob - AE6RV ___ 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 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] FE-5680A Voltage?
Hi Looking at the 2496 data sheet - you probably want to put something 20 volts into the board if you want a reasonable 15 volts out of it. Bob On Sep 12, 2013, at 8:01 PM, Bob Stewart b...@evoria.net wrote: I just remembered: Someone here or on the Agilent list suggested I buy a handful of those LM2596 buckboards a few weeks ago. That one wallwart should have enough headroom to give me 15V. Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, September 12, 2013 4:52 PM Subject: Re: [time-nuts] FE-5680A Voltage? Hi As I recall, 15 volts is sort of the minimum they recommend on most of the variations of the 5680. The internal regulators will probably be happier with 18 volts than with 14.25. You best bet is indeed a 15 V supply. Bob On Sep 12, 2013, at 11:03 AM, Bob Stewart b...@evoria.net wrote: I decided to order a Rb standard, and I was wondering what the lower limit on the 15V power requirement is? I have a PSU that will go up to 14.25V and my next closest is 18V. Should I just get a new 15V PSU before this gets in? Maybe I can make a quick mod on the big one and take it up to 15V. Bob - AE6RV ___ 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 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] FE-5680A Voltage?
I hadn't given it any thought. I saw some ad that said 1.5 volts so I assumed that. But, after looking through the datasheet I see an efficiency figure of 73 percent for the adjustable one, so that does imply a need for about 20.5 volts. OTOH, it says the feedback voltage is 1.23V, so I dunno. And I'm certainly not pretending I have any electrical design skills. I'll find out. =) Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, September 12, 2013 7:54 PM Subject: Re: [time-nuts] FE-5680A Voltage? Hi Looking at the 2496 data sheet - you probably want to put something 20 volts into the board if you want a reasonable 15 volts out of it. Bob On Sep 12, 2013, at 8:01 PM, Bob Stewart b...@evoria.net wrote: I just remembered: Someone here or on the Agilent list suggested I buy a handful of those LM2596 buckboards a few weeks ago. That one wallwart should have enough headroom to give me 15V. Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, September 12, 2013 4:52 PM Subject: Re: [time-nuts] FE-5680A Voltage? Hi As I recall, 15 volts is sort of the minimum they recommend on most of the variations of the 5680. The internal regulators will probably be happier with 18 volts than with 14.25. You best bet is indeed a 15 V supply. Bob On Sep 12, 2013, at 11:03 AM, Bob Stewart b...@evoria.net wrote: I decided to order a Rb standard, and I was wondering what the lower limit on the 15V power requirement is? I have a PSU that will go up to 14.25V and my next closest is 18V. Should I just get a new 15V PSU before this gets in? Maybe I can make a quick mod on the big one and take it up to 15V. Bob - AE6RV ___ 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 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 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] FE-5680A Voltage?
Looking at the LM2596 datasheet the switch transistor saturation voltage is 1.5V max at 3A (1.16v typ). That and an educated guess of about 0.25V for inductor loss combine to set the minimum difference between input and output. The 1.23V reference is about +/-3% accurate, so after setting the buckboard to 15.00V out (at 25C) expect it to shift at most 0.5V over time and temp. Add that to the minimum in-out difference and now you are at a minimum safe input of 2.25V above the nominal 15V output, or 17.25V in. An old 19V 3A laptop supply might be a good supply to use for this, if you were local I'd hand you one. As for efficiency, that just tells you the amount of heat the regulator, plus inductor, plus diode, etc. will throw off. FWIW the datasheet Figure 5 indicates you should expect about 88% or better efficiency for 15V out and at least 2V higher input voltage. (Doing some switching power supply design for a living does help with my understanding of them, but not ever enough!) Bob LaJeunesse From: Bob Stewart b...@evoria.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, September 12, 2013 9:28 PM Subject: Re: [time-nuts] FE-5680A Voltage? I hadn't given it any thought. I saw some ad that said 1.5 volts so I assumed that. But, after looking through the datasheet I see an efficiency figure of 73 percent for the adjustable one, so that does imply a need for about 20.5 volts. OTOH, it says the feedback voltage is 1.23V, so I dunno. And I'm certainly not pretending I have any electrical design skills. I'll find out. =) Bob ___ 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] FE-5680A Voltage?
Yes, my reading of the datasheet was the same. 18V in would be fine for 15V output. My concern would be how noisy the output would be. I have 9 of the from China ebay boards here (gave one to my boss to play with). I should wire one up and take a look. At any rate, I think a turn or two of the output wires through a ferrite bead would be in order. The data sheet shows a secondary filter of 3uH/180uF as well which I'd certainly want to use to feed a 5680A. Shouldn't do any harm, might do some good. Orin. On Thu, Sep 12, 2013 at 7:19 PM, Robert LaJeunesse rlajeune...@sbcglobal.net wrote: Looking at the LM2596 datasheet the switch transistor saturation voltage is 1.5V max at 3A (1.16v typ). That and an educated guess of about 0.25V for inductor loss combine to set the minimum difference between input and output. The 1.23V reference is about +/-3% accurate, so after setting the buckboard to 15.00V out (at 25C) expect it to shift at most 0.5V over time and temp. Add that to the minimum in-out difference and now you are at a minimum safe input of 2.25V above the nominal 15V output, or 17.25V in. An old 19V 3A laptop supply might be a good supply to use for this, if you were local I'd hand you one. As for efficiency, that just tells you the amount of heat the regulator, plus inductor, plus diode, etc. will throw off. FWIW the datasheet Figure 5 indicates you should expect about 88% or better efficiency for 15V out and at least 2V higher input voltage. (Doing some switching power supply design for a living does help with my understanding of them, but not ever enough!) Bob LaJeunesse ___ 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] FE-5680A Voltage?
Thanks for the input Orin! I'm trying to keep this from turning into the monumental effort my GPSDO had turned into, at least for the moment. So it's going to have to accept whatever the buckboard gives it, unless that's not enough. I just want to see what kind accuracy my GPSDO gives on the scope. Later on, I'll give it a decent place to live. Bob From: Orin Eman orin.e...@gmail.com To: Robert LaJeunesse lajeune...@mail.com; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, September 12, 2013 9:40 PM Subject: Re: [time-nuts] FE-5680A Voltage? Yes, my reading of the datasheet was the same. 18V in would be fine for 15V output. My concern would be how noisy the output would be. I have 9 of the from China ebay boards here (gave one to my boss to play with). I should wire one up and take a look. At any rate, I think a turn or two of the output wires through a ferrite bead would be in order. The data sheet shows a secondary filter of 3uH/180uF as well which I'd certainly want to use to feed a 5680A. Shouldn't do any harm, might do some good. Orin. On Thu, Sep 12, 2013 at 7:19 PM, Robert LaJeunesse rlajeune...@sbcglobal.net wrote: Looking at the LM2596 datasheet the switch transistor saturation voltage is 1.5V max at 3A (1.16v typ). That and an educated guess of about 0.25V for inductor loss combine to set the minimum difference between input and output. The 1.23V reference is about +/-3% accurate, so after setting the buckboard to 15.00V out (at 25C) expect it to shift at most 0.5V over time and temp. Add that to the minimum in-out difference and now you are at a minimum safe input of 2.25V above the nominal 15V output, or 17.25V in. An old 19V 3A laptop supply might be a good supply to use for this, if you were local I'd hand you one. As for efficiency, that just tells you the amount of heat the regulator, plus inductor, plus diode, etc. will throw off. FWIW the datasheet Figure 5 indicates you should expect about 88% or better efficiency for 15V out and at least 2V higher input voltage. (Doing some switching power supply design for a living does help with my understanding of them, but not ever enough!) Bob LaJeunesse ___ 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] FE-5680A Voltage tolerance
I've had one of mine running on a bench supply for about 2 days now. Have just tried turning the voltage down, and things started to get unstable at around 12.5V. It didn't drop out of lock however until about 9V. Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter Gottlieb Sent: 20 January 2012 04:16 To: time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A Voltage tolerance When I got my first unit I hooked it up to my protoboard power supply which is rated at 15 volts 0.5 amps and 5 volts 1 amp. I was annoyed that it took about 10 minutes to lock up until I realized the 15 volt supply was down near 11.5 volts. Oops. Substituting my small BK bench supply (good for up to 3 amps) resulted in a lock in under a couple of minutes. Perhaps my unit's internal adjustments are still just about right. It would be nice to get the alignment procedure for the thing, but I suppose, fat chance of that. Peter On 1/19/2012 6:45 PM, gonzo . wrote: Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. I thought this was interesting given several people report they are unable to get a lock when running lower voltage. ian ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1416 / Virus Database: 2109/4754 - Release Date: 01/19/12 ___ 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] FE-5680A Voltage tolerance
On Thu, 19 Jan 2012 16:29:35 -0800, Chris Albertson wrote: Could also be the all theses FE5680s don't have the same design. Already we've seen some don' have 5V regulators possably they changed the 15v side at some point? Chris Albertson Redondo Beach, California Besides the 2 cheap FE5680s i have (the ones that need 15v 5v) I have a FE5680 ($100+) that needs only 15v , this one has a PIC a DDS inside. The PIC can accept commands via rs232 , and then programs the DDS. It is supposedly adjustable in frequency from ?? to 20Mhz. CFO ___ 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] FE-5680A Voltage tolerance
It is not surprising that many of these units work alright below their specified voltage. I would imagine that the internal regulators, in addition to dropping voltage, are also there to keep voltages stable, and thus help with unit stability. So, a unit may work fine, and be able to meet stability specs, when operated slightly below the 15 volts, PROVIDED that that lower input voltage is provided by a stable, regulated supply. If I were the manufacturer, I would not want to have to rely on the supply being perfect, I would want to do my own regulation as they have. These are used in a system where the power supply drives many items and there are voltage drops due to wiring, backplanes, traces, etc as well as variations due to load changes. You may be able to have one unit work fine slightly below spec'd voltage, but if you do that in a system or with an unregulated supply and all bets are off. Give the unit decent power within its specified input range and then that's one thing you don't have to worry about further. Peter On 1/20/2012 6:09 AM, Rob Kimberley wrote: I've had one of mine running on a bench supply for about 2 days now. Have just tried turning the voltage down, and things started to get unstable at around 12.5V. It didn't drop out of lock however until about 9V. Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter Gottlieb Sent: 20 January 2012 04:16 To: time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A Voltage tolerance When I got my first unit I hooked it up to my protoboard power supply which is rated at 15 volts 0.5 amps and 5 volts 1 amp. I was annoyed that it took about 10 minutes to lock up until I realized the 15 volt supply was down near 11.5 volts. Oops. Substituting my small BK bench supply (good for up to 3 amps) resulted in a lock in under a couple of minutes. Perhaps my unit's internal adjustments are still just about right. It would be nice to get the alignment procedure for the thing, but I suppose, fat chance of that. Peter On 1/19/2012 6:45 PM, gonzo . wrote: Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. I thought this was interesting given several people report they are unable to get a lock when running lower voltage. ian ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1416 / Virus Database: 2109/4754 - Release Date: 01/19/12 ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1416 / Virus Database: 2109/4754 - Release Date: 01/19/12 ___ 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] FE-5680A Voltage tolerance
Starting Sunday I will do some voltage tests, giving up on aging test, nine weeks is long enough. I will se if the next one is as good, how ever I do not understand all the talk about running it at a lower voltage. Loosing regulation will definitely impact performance. I have not analysed my unit but a 13.3 V LDO was reported. In my opinion that says what the lower limit is based on sufficient margin for that regulator. What is wrong with 15 Volt? I am running the unit right out of the switcher no extra filtering and I can say based on my tests that it is good to 1 E-12. I also se a 4 Hz loop that will be there with any kind of regulation. That is why I will include a clean up OCXO with a 100 second analog filter. That OCXO will get special attention in its supply voltage regulation. Starting out with 15 Volt gives me enough head room. I am using a $ 10 12 V 2 A switcher cranked up to 15 V. Bert Kehren In a message dated 1/20/2012 7:43:16 A.M. Eastern Standard Time, n...@verizon.net writes: It is not surprising that many of these units work alright below their specified voltage. I would imagine that the internal regulators, in addition to dropping voltage, are also there to keep voltages stable, and thus help with unit stability. So, a unit may work fine, and be able to meet stability specs, when operated slightly below the 15 volts, PROVIDED that that lower input voltage is provided by a stable, regulated supply. If I were the manufacturer, I would not want to have to rely on the supply being perfect, I would want to do my own regulation as they have. These are used in a system where the power supply drives many items and there are voltage drops due to wiring, backplanes, traces, etc as well as variations due to load changes. You may be able to have one unit work fine slightly below spec'd voltage, but if you do that in a system or with an unregulated supply and all bets are off. Give the unit decent power within its specified input range and then that's one thing you don't have to worry about further. Peter On 1/20/2012 6:09 AM, Rob Kimberley wrote: I've had one of mine running on a bench supply for about 2 days now. Have just tried turning the voltage down, and things started to get unstable at around 12.5V. It didn't drop out of lock however until about 9V. Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter Gottlieb Sent: 20 January 2012 04:16 To: time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A Voltage tolerance When I got my first unit I hooked it up to my protoboard power supply which is rated at 15 volts 0.5 amps and 5 volts 1 amp. I was annoyed that it took about 10 minutes to lock up until I realized the 15 volt supply was down near 11.5 volts. Oops. Substituting my small BK bench supply (good for up to 3 amps) resulted in a lock in under a couple of minutes. Perhaps my unit's internal adjustments are still just about right. It would be nice to get the alignment procedure for the thing, but I suppose, fat chance of that. Peter On 1/19/2012 6:45 PM, gonzo . wrote: Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. I thought this was interesting given several people report they are unable to get a lock when running lower voltage. ian ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1416 / Virus Database: 2109/4754 - Release Date: 01/19/12 ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1416 / Virus Database: 2109/4754 - Release Date: 01/19/12 ___ 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] FE-5680A Voltage tolerance
Hi I think there are two somewhat independent things flowing through this thread. The first is - what is the real minimum voltage for this or that level of operation. The second is - what is the voltage for *best* operation. Every time I've been down this road before with an Rb, the answer to what's best has been a well regulated supply at the minimum specified input voltage. Varying the supply always seems to impact something and regulating supplies is easy these days. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of ewkeh...@aol.com Sent: Friday, January 20, 2012 8:01 AM To: time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A Voltage tolerance Starting Sunday I will do some voltage tests, giving up on aging test, nine weeks is long enough. I will se if the next one is as good, how ever I do not understand all the talk about running it at a lower voltage. Loosing regulation will definitely impact performance. I have not analysed my unit but a 13.3 V LDO was reported. In my opinion that says what the lower limit is based on sufficient margin for that regulator. What is wrong with 15 Volt? I am running the unit right out of the switcher no extra filtering and I can say based on my tests that it is good to 1 E-12. I also se a 4 Hz loop that will be there with any kind of regulation. That is why I will include a clean up OCXO with a 100 second analog filter. That OCXO will get special attention in its supply voltage regulation. Starting out with 15 Volt gives me enough head room. I am using a $ 10 12 V 2 A switcher cranked up to 15 V. Bert Kehren In a message dated 1/20/2012 7:43:16 A.M. Eastern Standard Time, n...@verizon.net writes: It is not surprising that many of these units work alright below their specified voltage. I would imagine that the internal regulators, in addition to dropping voltage, are also there to keep voltages stable, and thus help with unit stability. So, a unit may work fine, and be able to meet stability specs, when operated slightly below the 15 volts, PROVIDED that that lower input voltage is provided by a stable, regulated supply. If I were the manufacturer, I would not want to have to rely on the supply being perfect, I would want to do my own regulation as they have. These are used in a system where the power supply drives many items and there are voltage drops due to wiring, backplanes, traces, etc as well as variations due to load changes. You may be able to have one unit work fine slightly below spec'd voltage, but if you do that in a system or with an unregulated supply and all bets are off. Give the unit decent power within its specified input range and then that's one thing you don't have to worry about further. Peter On 1/20/2012 6:09 AM, Rob Kimberley wrote: I've had one of mine running on a bench supply for about 2 days now. Have just tried turning the voltage down, and things started to get unstable at around 12.5V. It didn't drop out of lock however until about 9V. Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter Gottlieb Sent: 20 January 2012 04:16 To: time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A Voltage tolerance When I got my first unit I hooked it up to my protoboard power supply which is rated at 15 volts 0.5 amps and 5 volts 1 amp. I was annoyed that it took about 10 minutes to lock up until I realized the 15 volt supply was down near 11.5 volts. Oops. Substituting my small BK bench supply (good for up to 3 amps) resulted in a lock in under a couple of minutes. Perhaps my unit's internal adjustments are still just about right. It would be nice to get the alignment procedure for the thing, but I suppose, fat chance of that. Peter On 1/19/2012 6:45 PM, gonzo . wrote: Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. I thought this was interesting given several people report they are unable to get a lock when running lower voltage. ian ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1416 / Virus Database: 2109/4754 - Release Date: 01/19/12 ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version
[time-nuts] FE-5680A Voltage tolerance
Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. I thought this was interesting given several people report they are unable to get a lock when running lower voltage. ian ___ 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] FE-5680A Voltage tolerance
Very interesting data. I wonder if this has to do with the nominal center frequency of the internal 60 MHz VCXO (which is divided by 6 to generate the 10 MHz output). On my units, the center frequency is pretty low and the 10 MHz output is near the top of the range (actually beyond the range on one unit, so it would never lock, until I tweaked the C217 trimmer). If there's an internal supply rail that sags even slightly, that would probably put at least one of my units out of lock range. Of course there's more to the whole system, maybe the Rb doesn't reach temperature, or the microwave section droops or has inadequate power level, etc. I'd suspect even if the unit does work at very low voltages, it is more marginal, noisy and less stable. It is surprising that it works at all below 11 V input, though. -John Beale From: gonzo . cadbl...@hotmail.com Subject: [time-nuts] FE-5680A Voltage tolerance Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. ___ 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] FE-5680A Voltage tolerance
On Thu, Jan 19, 2012 at 3:45 PM, gonzo . cadbl...@hotmail.com wrote: Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. It looks like I simply gave up to soon. I waited about double the normal time for lock and assumed it would never happen. I figured there must be a regulator inside and I was below its drop out range. Could also be the all theses FE5680s don't have the same design. Already we've seen some don' have 5V regulators possably they changed the 15v side at some point? Chris Albertson Redondo Beach, California ___ 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] FE-5680A Voltage tolerance
I would expect the RF circuitry to handle a lower voltage without too much trouble. However, a lower input voltage means it will take longer for the ovens to come up to temperature. Until they stabilize, a lock probably won't happen. Once the unit has warmed up and locked, how low can you go and still maintain lock? As you drop the voltage, the ovens will run closer to full on. Once you reach the point where one or more of the ovens are full on, further voltage reduction will quickly cause issues. Ed On 1/19/2012 5:45 PM, gonzo . wrote: Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. I thought this was interesting given several people report they are unable to get a lock when running lower voltage. ian ___ 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] FE-5680A Voltage tolerance
As soon as my next unit comes in I will run some controlled tests. This one refuses to show aging with week 9 up in two days. I will use it for other tests before I take it appart. Bert In a message dated 1/19/2012 8:18:10 P.M. Eastern Standard Time, ed_pal...@sasktel.net writes: I would expect the RF circuitry to handle a lower voltage without too much trouble. However, a lower input voltage means it will take longer for the ovens to come up to temperature. Until they stabilize, a lock probably won't happen. Once the unit has warmed up and locked, how low can you go and still maintain lock? As you drop the voltage, the ovens will run closer to full on. Once you reach the point where one or more of the ovens are full on, further voltage reduction will quickly cause issues. Ed On 1/19/2012 5:45 PM, gonzo . wrote: Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. I thought this was interesting given several people report they are unable to get a lock when running lower voltage. ian ___ 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] FE-5680A Voltage tolerance
Speaking of aging, can anyone explain FEI's spec for aging on the 5680A? 2e-11 per DAY? Seriously? Everyone else specs their Rb standards in the Xe-11 range per MONTH. When I first saw it, I thought it was just a typo, but it's in multiple documents and web pages and it's been there for years. Ed On 1/19/2012 7:35 PM, ewkeh...@aol.com wrote: As soon as my next unit comes in I will run some controlled tests. This one refuses to show aging with week 9 up in two days. I will use it for other tests before I take it appart. Bert In a message dated 1/19/2012 8:18:10 P.M. Eastern Standard Time, ed_pal...@sasktel.net writes: I would expect the RF circuitry to handle a lower voltage without too much trouble. However, a lower input voltage means it will take longer for the ovens to come up to temperature. Until they stabilize, a lock probably won't happen. Once the unit has warmed up and locked, how low can you go and still maintain lock? As you drop the voltage, the ovens will run closer to full on. Once you reach the point where one or more of the ovens are full on, further voltage reduction will quickly cause issues. Ed On 1/19/2012 5:45 PM, gonzo . wrote: Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. I thought this was interesting given several people report they are unable to get a lock when running lower voltage. ian ___ 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] FE-5680A Voltage tolerance
When I got my first unit I hooked it up to my protoboard power supply which is rated at 15 volts 0.5 amps and 5 volts 1 amp. I was annoyed that it took about 10 minutes to lock up until I realized the 15 volt supply was down near 11.5 volts. Oops. Substituting my small BK bench supply (good for up to 3 amps) resulted in a lock in under a couple of minutes. Perhaps my unit's internal adjustments are still just about right. It would be nice to get the alignment procedure for the thing, but I suppose, fat chance of that. Peter On 1/19/2012 6:45 PM, gonzo . wrote: Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. I thought this was interesting given several people report they are unable to get a lock when running lower voltage. ian ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1416 / Virus Database: 2109/4754 - Release Date: 01/19/12 ___ 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.
