Re: [time-nuts] Effects of noise on EFC line? - Resolved

[Bob Stewart]

Hi Bob,

I hadn't even considered a filter in the OCXO.  This isn't a 10811, but that's 
the OCXO I have a schematic of, so I'll assume that's the benchmark.  Following 
the EFC in, it looks like it goes to a 100K resistor and then tees to the 100pf 
varicap and a 15pf to the xtal.  Other caps are attached as well, but it 
doesn't look like it's bypassed to ground anywhere along the EFC line.  I see 
that there's another 100K to a 6.4V reference with a 6.8uf cap.  So, that means 
that the EFC line ranges from +6.4 to -6.4?  I haven't worked out the time 
constant, but that wouldn't seem to apply for a 10MHz signal riding on the EFC 
voltage.


Like I said, I don't have a 10811 on my GPSDO.  It's my faithful Trimble 
34310-T.  Still, I would imagine that they at least looked at HP's design.

As to Hal's comment about probe pickup.  I was careful to specify the X10 
position of the probe.  In the X1 position there was a signal that wasn't 
visible in X10, but should have been.  So, I assumed that was some sort of 
induced signal.  I'm using a generic cheap Chinese probe available on ebay.


Bob




 From: Bob Camp 
To: Discussion of precise time and frequency measurement  
Sent: Thursday, August 7, 2014 6:11 PM
Subject: Re: [time-nuts] Effects of noise on EFC line? - Resolved
 

Hi

Your EFC line is probably bypassed internally to the OCXO. A 3db modulation 
bandwidth beyond 1 KHz is unlikely. A modulation bandwidth below 100 Hz is 
quite possible. 

Next thing to consider is that the EFC does FM on the OCXO. Phase noise is PM 
modulation. FM is 1/Fmod relative to PM. If I go up a decade in frequency with 
constant FM, my PM sideband will go down by 20 db. Yes that’s for small 
modulation indexes. That’s very likely the case if we are dealing with noise. 

You can calculate exactly what PM sideband in dbc you will get from a 1 Hz tone 
at 1 mV p-p on your EFC. From that you can pretty quickly work out what this or 
that number of microvolts will do at this or that frequency.  The answer is 
normally that the noise you have from a reasonable regulator or op-amp isn’t a 
big deal. 

Bob
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Re: [time-nuts] Effects of noise on EFC line? - Resolved

[Alex Pummer]

he is on the right truck, just look around in your testing environment, 
do you have shielded test set up, common ground for all the test gears ?


 On 8/7/2014 3:58 PM, Hal Murray wrote:

b...@evoria.net said:

So, I may throw another cap on it, but it seems to be clean down to what I
can measure at the OCXO on my old Tek 455 with an X10 probe.

Another thing to consider when chasing that sort of problem: How much are you
picking up with your scope probe and/or its ground wire?

The classic home brew better-probe is to use a chunk of 50 ohm coax feeding
into scope with a 50 ohm terminator.  (You get 2 of them if you cut a readily
available connectorized cable in half.)  Insert 950 ohms at the probe end to
get higher input impedance at the cost of a 20:1 divider.
   http://www.signalintegrity.com/Pubs/straight/probes.htm

It usually requires soldering at the DUT.  For me, it also requires a mental
shift.  You have to think of your scope probe as a consumable rather than
something that won't wear out if you take care of it.  A chunk of coax will
last a long time.  Just cut off another 1/2 inch when the end gets too
mangled.




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Re: [time-nuts] Low noise powersupplies

[Alexander Pummer]

people who designing low noise PLLs solved that problem a while ego go 
to Charles Wenzels circuit collections he made a very low noise from DC 
to a few hundred kHz amplifier just to amplify the phase noise, here is:

http://www.techlib.com/files/lowamp.pdf


On 8/7/2014 5:05 PM, Bob Camp wrote:

Hi

A low noise chopper stabilized op amp can make a pretty good pre-amp to put in 
front of a low frequency spectrum analyzer. Something in the 20 to 30 db gain 
is adequate for most analyzers. That will get you down to a level that’s well 
below the noise floor on any OCXO I have ever seen.

Here’s a way to look at it:

The input resistors on the OCXO have KBT noise (they are real resistors). They 
also are in the “many thousands of ohms” range. If you short the EFC (zero 
noise in) you still have resistor voltage noise modulating the EFC. All you 
need to do is to get down to the KTB level in a few thousand ohm resistor.

Yes 1/F noise does get into the mix. That’s why you want the chopper.

Bob
  
On Aug 7, 2014, at 6:32 PM, Alex Pummer  wrote:




the PC sound card has limited bandwidth   bellow 20Hz and above 20kHz, is nothing and 
also it is not so "noise less" like a spectrum analyzer which was made to 
analyze spectrum and the sound card self is in a relative noisy environment in the PC

On 8/7/2014 3:09 PM, Bob Stewart wrote:

What about a PC sound card?




  From: Alexander Pummer 
To: Discussion of precise time and frequency measurement 
Sent: Thursday, August 7, 2014 5:06 PM
Subject: Re: [time-nuts] Low noise powersupplies
  
to measure a power supply noise, better to say the noise spectrum,  you

would need a very large non polarized capacitor and spectrum analyzer,
The input of the spectrum analyzer does not like DC, and has low
impedance. Since spectrum analyzer's input impedance is usually 50 ohm,
for to be able to see the noise at low frequency you need  C = 1/( 2 x
3.14 x 50 ohm x f Hz ) capacitor, and you would need a DC level limiter
to prevent blowing the input of the spectrum analyzer during the charge
up of that capacitor. If you could get a hold of an old HP 1Meg to 50ohm
buffer amplifier you would need much lover capacitance or if  the buffer
has AC input capability with low enough corner frequency like  the
Tektronix P6201 FET probe, you would not need any capacitor. And that
would make your life much nicer since capacitors could generate noise to..
Charles Wenzel  in his circuit collection files ha very nice good
working noise reduction circuits.
73
Alex
KJ6UHN
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Re: [time-nuts] Low noise powersupplies

[Bob Camp]

Hi

A low noise chopper stabilized op amp can make a pretty good pre-amp to put in 
front of a low frequency spectrum analyzer. Something in the 20 to 30 db gain 
is adequate for most analyzers. That will get you down to a level that’s well 
below the noise floor on any OCXO I have ever seen.

Here’s a way to look at it:

The input resistors on the OCXO have KBT noise (they are real resistors). They 
also are in the “many thousands of ohms” range. If you short the EFC (zero 
noise in) you still have resistor voltage noise modulating the EFC. All you 
need to do is to get down to the KTB level in a few thousand ohm resistor. 

Yes 1/F noise does get into the mix. That’s why you want the chopper. 

Bob
 
On Aug 7, 2014, at 6:32 PM, Alex Pummer  wrote:

> 
> 
> the PC sound card has limited bandwidth   bellow 20Hz and above 20kHz, is 
> nothing and also it is not so "noise less" like a spectrum analyzer which was 
> made to analyze spectrum and the sound card self is in a relative noisy 
> environment in the PC
> 
> On 8/7/2014 3:09 PM, Bob Stewart wrote:
>> What about a PC sound card?
>> 
>> 
>> 
>> 
>>  From: Alexander Pummer 
>> To: Discussion of precise time and frequency measurement 
>> Sent: Thursday, August 7, 2014 5:06 PM
>> Subject: Re: [time-nuts] Low noise powersupplies
>>  
>> to measure a power supply noise, better to say the noise spectrum,  you
>> would need a very large non polarized capacitor and spectrum analyzer,
>> The input of the spectrum analyzer does not like DC, and has low
>> impedance. Since spectrum analyzer's input impedance is usually 50 ohm,
>> for to be able to see the noise at low frequency you need  C = 1/( 2 x
>> 3.14 x 50 ohm x f Hz ) capacitor, and you would need a DC level limiter
>> to prevent blowing the input of the spectrum analyzer during the charge
>> up of that capacitor. If you could get a hold of an old HP 1Meg to 50ohm
>> buffer amplifier you would need much lover capacitance or if  the buffer
>> has AC input capability with low enough corner frequency like  the
>> Tektronix P6201 FET probe, you would not need any capacitor. And that
>> would make your life much nicer since capacitors could generate noise to..
>> Charles Wenzel  in his circuit collection files ha very nice good
>> working noise reduction circuits.
>> 73
>> Alex
>> KJ6UHN
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> 
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Re: [time-nuts] Low noise power supplies

[Charles Steinmetz]

Chris wrote:

Just practical question.. How would one measure noise at this 
level?  If I were evaluate this what would I need?


Generally, one starts with an extremely low noise amplifier.  Note 
that isolating the very low frequency AC components from the DC 
component is a substantial difficulty (we are interested in AC noise 
well below 1 Hz).  For example:




See also:

Linear Technology Application Notes 124 and 83

Bruno Neri, et al., Ultra Low-Noise Preamplifier for Low-Frequency 
Noise Measurements in Electron Devices, IEEE Transactions On 
Instrumentation And Measurement, Vol. 40. No. I. February 1991


Felix A. Levinzon, Ultra-Low-Noise High-Input Impedance Amplifier for 
Low-Frequency Measurement Applications, IEEE Transactions On Circuits 
And Systems - I: Regular Papers, Vol. 55, No. 7, August 2008


Some spectrum analyzers with cross-correlation capabilities can get 
you in the ballpark if you let them average long enough, although you 
are much better off if you use an ELN amplifier there, too.


Best regards,

Charles



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Re: [time-nuts] Effects of noise on EFC line? - Resolved

[Bob Camp]

Hi

Your EFC line is probably bypassed internally to the OCXO. A 3db modulation 
bandwidth beyond 1 KHz is unlikely. A modulation bandwidth below 100 Hz is 
quite possible. 

Next thing to consider is that the EFC does FM on the OCXO. Phase noise is PM 
modulation. FM is 1/Fmod relative to PM. If I go up a decade in frequency with 
constant FM, my PM sideband will go down by 20 db. Yes that’s for small 
modulation indexes. That’s very likely the case if we are dealing with noise. 

You can calculate exactly what PM sideband in dbc you will get from a 1 Hz tone 
at 1 mV p-p on your EFC. From that you can pretty quickly work out what this or 
that number of microvolts will do at this or that frequency.  The answer is 
normally that the noise you have from a reasonable regulator or op-amp isn’t a 
big deal. 

Bob


On Aug 7, 2014, at 6:58 PM, Hal Murray  wrote:

> 
> b...@evoria.net said:
>> So, I may throw another cap on it, but it seems to be clean down to what I
>> can measure at the OCXO on my old Tek 455 with an X10 probe. 
> 
> Another thing to consider when chasing that sort of problem: How much are you 
> picking up with your scope probe and/or its ground wire?
> 
> The classic home brew better-probe is to use a chunk of 50 ohm coax feeding 
> into scope with a 50 ohm terminator.  (You get 2 of them if you cut a readily 
> available connectorized cable in half.)  Insert 950 ohms at the probe end to 
> get higher input impedance at the cost of a 20:1 divider.
>  http://www.signalintegrity.com/Pubs/straight/probes.htm
> 
> It usually requires soldering at the DUT.  For me, it also requires a mental 
> shift.  You have to think of your scope probe as a consumable rather than 
> something that won't wear out if you take care of it.  A chunk of coax will 
> last a long time.  Just cut off another 1/2 inch when the end gets too 
> mangled.
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
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Re: [time-nuts] Low noise powersupplies

[Alex Pummer]

the PC sound card has limited bandwidth   bellow 20Hz and above 20kHz, 
is nothing and also it is not so "noise less" like a spectrum analyzer 
which was made to analyze spectrum and the sound card self is in a 
relative noisy environment in the PC


On 8/7/2014 3:09 PM, Bob Stewart wrote:

What about a PC sound card?




  From: Alexander Pummer 
To: Discussion of precise time and frequency measurement 
Sent: Thursday, August 7, 2014 5:06 PM
Subject: Re: [time-nuts] Low noise powersupplies
  


to measure a power supply noise, better to say the noise spectrum,  you
would need a very large non polarized capacitor and spectrum analyzer,
The input of the spectrum analyzer does not like DC, and has low
impedance. Since spectrum analyzer's input impedance is usually 50 ohm,
for to be able to see the noise at low frequency you need  C = 1/( 2 x
3.14 x 50 ohm x f Hz ) capacitor, and you would need a DC level limiter
to prevent blowing the input of the spectrum analyzer during the charge
up of that capacitor. If you could get a hold of an old HP 1Meg to 50ohm
buffer amplifier you would need much lover capacitance or if  the buffer
has AC input capability with low enough corner frequency like  the
Tektronix P6201 FET probe, you would not need any capacitor. And that
would make your life much nicer since capacitors could generate noise to..
Charles Wenzel  in his circuit collection files ha very nice good
working noise reduction circuits.
73
Alex
KJ6UHN
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Re: [time-nuts] Effects of noise on EFC line? - Resolved

[Hal Murray]

b...@evoria.net said:
> So, I may throw another cap on it, but it seems to be clean down to what I
> can measure at the OCXO on my old Tek 455 with an X10 probe. 

Another thing to consider when chasing that sort of problem: How much are you 
picking up with your scope probe and/or its ground wire?

The classic home brew better-probe is to use a chunk of 50 ohm coax feeding 
into scope with a 50 ohm terminator.  (You get 2 of them if you cut a readily 
available connectorized cable in half.)  Insert 950 ohms at the probe end to 
get higher input impedance at the cost of a 20:1 divider.
  http://www.signalintegrity.com/Pubs/straight/probes.htm

It usually requires soldering at the DUT.  For me, it also requires a mental 
shift.  You have to think of your scope probe as a consumable rather than 
something that won't wear out if you take care of it.  A chunk of coax will 
last a long time.  Just cut off another 1/2 inch when the end gets too 
mangled.


-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] Low noise powersupplies

[Bob Stewart]

What about a PC sound card?




 From: Alexander Pummer 
To: Discussion of precise time and frequency measurement  
Sent: Thursday, August 7, 2014 5:06 PM
Subject: Re: [time-nuts] Low noise powersupplies
 

to measure a power supply noise, better to say the noise spectrum,  you 
would need a very large non polarized capacitor and spectrum analyzer, 
The input of the spectrum analyzer does not like DC, and has low 
impedance. Since spectrum analyzer's input impedance is usually 50 ohm, 
for to be able to see the noise at low frequency you need  C = 1/( 2 x 
3.14 x 50 ohm x f Hz ) capacitor, and you would need a DC level limiter 
to prevent blowing the input of the spectrum analyzer during the charge 
up of that capacitor. If you could get a hold of an old HP 1Meg to 50ohm 
buffer amplifier you would need much lover capacitance or if  the buffer 
has AC input capability with low enough corner frequency like  the 
Tektronix P6201 FET probe, you would not need any capacitor. And that 
would make your life much nicer since capacitors could generate noise to..
Charles Wenzel  in his circuit collection files ha very nice good 
working noise reduction circuits.
73
Alex
KJ6UHN
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Re: [time-nuts] Low noise powersupplies

[Alexander Pummer]

to measure a power supply noise, better to say the noise spectrum,  you 
would need a very large non polarized capacitor and spectrum analyzer, 
The input of the spectrum analyzer does not like DC, and has low 
impedance. Since spectrum analyzer's input impedance is usually 50 ohm, 
for to be able to see the noise at low frequency you need  C = 1/( 2 x 
3.14 x 50 ohm x f Hz ) capacitor, and you would need a DC level limiter 
to prevent blowing the input of the spectrum analyzer during the charge 
up of that capacitor. If you could get a hold of an old HP 1Meg to 50ohm 
buffer amplifier you would need much lover capacitance or if  the buffer 
has AC input capability with low enough corner frequency like  the 
Tektronix P6201 FET probe, you would not need any capacitor. And that 
would make your life much nicer since capacitors could generate noise to..
Charles Wenzel  in his circuit collection files ha very nice good 
working noise reduction circuits.

73
Alex
KJ6UHN

On 8/7/2014 1:41 PM, Chris Albertson wrote:

Just practical question..

How would one measure noise at this level?  If I were evaluate this what
would I need?  My scope lacks a nV/dev setting so is there some way to tell
the difference between this and an LM317?  Seriously, what kind of
instrumentation would I need before I could measure an improvement over my
"standard" LM317



On Wed, Aug 6, 2014 at 11:38 PM, Ole Petter Ronningen 
wrote:


Hello, all

I thought it may be of interest to some of the members of this list that TI
is selling evaluation modules for some ultra low noise regulators for $20
in their estore, shipping world wide included. The specs looks pretty
decent to me, and I've ordered up a couple of boards to use as "clean up
boxes" for my bench-supplies, to use on noise-sensitive projects.

1.4-30v output TPS7A4701EVM-094
3.5µVRMS (10Hz, 100KHz)
<25 nV/√Hz (10Hz, 1MHz)
Maximum Output Current of 1A

+-15v version TPS7A30-49EVM-567:
15v rail:
Noise:
  12.7µVRMS (20Hz to 20kHz)
  15.4µVRMS (10Hz to 100kHz)
Power-Supply Ripple Rejection:
  72dB (120Hz)
  ≥ 52dB (10Hz to 400kHz)
Maximum Output Current: 150mA


-15v rail:
Noise:
  14µVRMS (20Hz to 20kHz)
  15.1µVRMS (10Hz to 100kHz)
Power-Supply Ripple Rejection:
  72dB (120Hz)
  ≥ 55dB (10Hz to 700kHz)
Maximum Output Current: 200mA

Ole
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Re: [time-nuts] Low noise powersupplies

[Chris Albertson]

Just practical question..

How would one measure noise at this level?  If I were evaluate this what
would I need?  My scope lacks a nV/dev setting so is there some way to tell
the difference between this and an LM317?  Seriously, what kind of
instrumentation would I need before I could measure an improvement over my
"standard" LM317



On Wed, Aug 6, 2014 at 11:38 PM, Ole Petter Ronningen 
wrote:

> Hello, all
>
> I thought it may be of interest to some of the members of this list that TI
> is selling evaluation modules for some ultra low noise regulators for $20
> in their estore, shipping world wide included. The specs looks pretty
> decent to me, and I've ordered up a couple of boards to use as "clean up
> boxes" for my bench-supplies, to use on noise-sensitive projects.
>
> 1.4-30v output TPS7A4701EVM-094
> 3.5µVRMS (10Hz, 100KHz)
> <25 nV/√Hz (10Hz, 1MHz)
> Maximum Output Current of 1A
>
> +-15v version TPS7A30-49EVM-567:
> 15v rail:
> Noise:
>  12.7µVRMS (20Hz to 20kHz)
>  15.4µVRMS (10Hz to 100kHz)
> Power-Supply Ripple Rejection:
>  72dB (120Hz)
>  ≥ 52dB (10Hz to 400kHz)
> Maximum Output Current: 150mA
>
>
> -15v rail:
> Noise:
>  14µVRMS (20Hz to 20kHz)
>  15.1µVRMS (10Hz to 100kHz)
> Power-Supply Ripple Rejection:
>  72dB (120Hz)
>  ≥ 55dB (10Hz to 700kHz)
> Maximum Output Current: 200mA
>
> Ole
> ___
> time-nuts mailing list -- time-nuts@febo.com
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> and follow the instructions there.




-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] Low noise powersupplies

[David Hooke]

Such as?

david

On 7/08/2014 9:30 PM, bruce-cpdlzquo8hwavxtiumw...@public.gmane.org wrote:

I have a couple of these. however their noise spectral density tends
  to rise precipitously below 1Hz or so. There  are regulators with 
significantly
lower flicker noise.

Bruce



On August 7, 2014 at 6:35 AM Tom Van Baak  wrote:


Ole,

Thanks for bringing it to our attention.
For those that like to click instead of search:

http://www.ti.com/tool/TPS7A4701EVM-094
http://www.ti.com/lit/ug/slvu741a/slvu741a.pdf
http://www.ti.com/product/tps7a4701
http://www.ti.com/lit/ds/symlink/tps7a4701.pdf

/tvb

- Original Message -
From: "Ole Petter Ronningen" 
To: 
Sent: Wednesday, August 06, 2014 11:38 PM
Subject: [time-nuts] Low noise powersupplies



Hello, all

I thought it may be of interest to some of the members of this list that TI
is selling evaluation modules for some ultra low noise regulators for $20
in their estore, shipping world wide included. The specs looks pretty
decent to me, and I've ordered up a couple of boards to use as "clean up
boxes" for my bench-supplies, to use on noise-sensitive projects.

1.4-30v output TPS7A4701EVM-094
3.5µVRMS (10Hz, 100KHz)
<25 nV/√Hz (10Hz, 1MHz)
Maximum Output Current of 1A

+-15v version TPS7A30-49EVM-567:
15v rail:
Noise:
12.7µVRMS (20Hz to 20kHz)
15.4µVRMS (10Hz to 100kHz)
Power-Supply Ripple Rejection:
72dB (120Hz)
≥ 52dB (10Hz to 400kHz)
Maximum Output Current: 150mA


-15v rail:
Noise:
14µVRMS (20Hz to 20kHz)
15.1µVRMS (10Hz to 100kHz)
Power-Supply Ripple Rejection:
72dB (120Hz)
≥ 55dB (10Hz to 700kHz)
Maximum Output Current: 200mA

Ole



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Re: [time-nuts] Low noise powersupplies

[br...@ko4bb.com]

I have a couple of these. however their noise spectral density tends
 to rise precipitously below 1Hz or so. There  are regulators with significantly
lower flicker noise.

Bruce


> On August 7, 2014 at 6:35 AM Tom Van Baak  wrote:
>
>
> Ole,
>
> Thanks for bringing it to our attention.
> For those that like to click instead of search:
>
> http://www.ti.com/tool/TPS7A4701EVM-094
> http://www.ti.com/lit/ug/slvu741a/slvu741a.pdf
> http://www.ti.com/product/tps7a4701
> http://www.ti.com/lit/ds/symlink/tps7a4701.pdf
>
> /tvb
>
> - Original Message -
> From: "Ole Petter Ronningen" 
> To: 
> Sent: Wednesday, August 06, 2014 11:38 PM
> Subject: [time-nuts] Low noise powersupplies
>
>
> > Hello, all
> >
> > I thought it may be of interest to some of the members of this list that TI
> > is selling evaluation modules for some ultra low noise regulators for $20
> > in their estore, shipping world wide included. The specs looks pretty
> > decent to me, and I've ordered up a couple of boards to use as "clean up
> > boxes" for my bench-supplies, to use on noise-sensitive projects.
> >
> > 1.4-30v output TPS7A4701EVM-094
> > 3.5µVRMS (10Hz, 100KHz)
> > <25 nV/√Hz (10Hz, 1MHz)
> > Maximum Output Current of 1A
> >
> > +-15v version TPS7A30-49EVM-567:
> > 15v rail:
> > Noise:
> > 12.7µVRMS (20Hz to 20kHz)
> > 15.4µVRMS (10Hz to 100kHz)
> > Power-Supply Ripple Rejection:
> > 72dB (120Hz)
> > ≥ 52dB (10Hz to 400kHz)
> > Maximum Output Current: 150mA
> >
> >
> > -15v rail:
> > Noise:
> > 14µVRMS (20Hz to 20kHz)
> > 15.1µVRMS (10Hz to 100kHz)
> > Power-Supply Ripple Rejection:
> > 72dB (120Hz)
> > ≥ 55dB (10Hz to 700kHz)
> > Maximum Output Current: 200mA
> >
> > Ole
>
>
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Re: [time-nuts] Low noise powersupplies

[Tom Van Baak]

Ole,

Thanks for bringing it to our attention.
For those that like to click instead of search:

http://www.ti.com/tool/TPS7A4701EVM-094
http://www.ti.com/lit/ug/slvu741a/slvu741a.pdf
http://www.ti.com/product/tps7a4701
http://www.ti.com/lit/ds/symlink/tps7a4701.pdf

/tvb

- Original Message - 
From: "Ole Petter Ronningen" 
To: 
Sent: Wednesday, August 06, 2014 11:38 PM
Subject: [time-nuts] Low noise powersupplies


> Hello, all
> 
> I thought it may be of interest to some of the members of this list that TI
> is selling evaluation modules for some ultra low noise regulators for $20
> in their estore, shipping world wide included. The specs looks pretty
> decent to me, and I've ordered up a couple of boards to use as "clean up
> boxes" for my bench-supplies, to use on noise-sensitive projects.
> 
> 1.4-30v output TPS7A4701EVM-094
> 3.5µVRMS (10Hz, 100KHz)
> <25 nV/√Hz (10Hz, 1MHz)
> Maximum Output Current of 1A
> 
> +-15v version TPS7A30-49EVM-567:
> 15v rail:
> Noise:
> 12.7µVRMS (20Hz to 20kHz)
> 15.4µVRMS (10Hz to 100kHz)
> Power-Supply Ripple Rejection:
> 72dB (120Hz)
> ≥ 52dB (10Hz to 400kHz)
> Maximum Output Current: 150mA
> 
> 
> -15v rail:
> Noise:
> 14µVRMS (20Hz to 20kHz)
> 15.1µVRMS (10Hz to 100kHz)
> Power-Supply Ripple Rejection:
> 72dB (120Hz)
> ≥ 55dB (10Hz to 700kHz)
> Maximum Output Current: 200mA
> 
> Ole


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[time-nuts] Low noise powersupplies

[Ole Petter Ronningen]

Hello, all

I thought it may be of interest to some of the members of this list that TI
is selling evaluation modules for some ultra low noise regulators for $20
in their estore, shipping world wide included. The specs looks pretty
decent to me, and I've ordered up a couple of boards to use as "clean up
boxes" for my bench-supplies, to use on noise-sensitive projects.

1.4-30v output TPS7A4701EVM-094
3.5µVRMS (10Hz, 100KHz)
<25 nV/√Hz (10Hz, 1MHz)
Maximum Output Current of 1A

+-15v version TPS7A30-49EVM-567:
15v rail:
Noise:
 12.7µVRMS (20Hz to 20kHz)
 15.4µVRMS (10Hz to 100kHz)
Power-Supply Ripple Rejection:
 72dB (120Hz)
 ≥ 52dB (10Hz to 400kHz)
Maximum Output Current: 150mA


-15v rail:
Noise:
 14µVRMS (20Hz to 20kHz)
 15.1µVRMS (10Hz to 100kHz)
Power-Supply Ripple Rejection:
 72dB (120Hz)
 ≥ 55dB (10Hz to 700kHz)
Maximum Output Current: 200mA

Ole
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