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Low Jitter 20MHz oscillator

Started by hbv March 1, 2013
On 01/03/2013 18:07, Jim Thompson wrote:
> You can easily slap one together with a 74HCU04. Just make sure it's > the "U" version.
Hello Jim, What do you mean with "slap together with a U version" ? I believe an integrated oscillator will not gain benefit with an additional U version of anything. Best regards, Habib
On 02/03/2013 01:40, John Larkin wrote:
> On Fri, 01 Mar 2013 14:41:08 +0100, hbv <habib.bouaziz@gmail.com> > wrote: > >> Hi all, >> >> We need a low jitter clock generator ( 3v3 or 1v8 CMOS output single >> ended ), 20Mhz (+-few percent...) and most important a low jitter on >> this output (few ps). >> >> Any ideas are welcomed. Habib. > > How do you plan to measure the jitter? > > Why does it matter? > >
John, Measuring jitter is really the point (method based on something which ressemble on eye diag or something like that ... i don't know at the moment) the best is that i would not measure anything like that, just based on component spec. I need a CMOS low jitter oscillator (few ps in absolute way) only on specs for feeding the clock input of an16bits AD converter (is that so hard ?) Some guys said that a basic 74HCU would be sufficient ... i did'nt read anything such a thing on any 74HCUxx datasheet. I remember i had used IDT chips feeding a 100MHz PLL clock input for a PPC (AMCC PPC440) with something like 1 or 2 ps absolute jitter. I'm expecting that it's not so hard to find the equivalent on 20MHz. I will manage the point this week. Thx anyway for the topic. Habib
On Mar 3, 12:04=A0am, Habib Bouaziz-Viallet <h.bouazizvial...@free.fr>
wrote:
> On 01/03/2013 18:07, Jim Thompson wrote:> You can easily slap one togethe=
r with a 74HCU04. =A0Just make sure it's
> > the "U" version. > > Hello Jim, > > What do you mean with "slap together with a U version" ? I believe an > integrated oscillator will not gain benefit with an additional U version > of anything. > > Best regards, Habib
A 74HCU04,an xtal, 2 caps, 2 resistors and you have a very nice oscillator -Lasse
On 01/03/2013 18:48, Spehro Pefhany wrote:
> Conner-Winfield DV75C series has maximum integrated phase jitter 1ps > RMS over 12kHz to 20MHz
Really good point, thank you. But for the silabs solutions i think these guys are too obfuscated ... and i'm too in a hurry. Best Regards, Habib.
On 03/03/2013 00:09, langwadt@fonz.dk wrote:
> A 74HCU04,an xtal, 2 caps, 2 resistors and you have a very nice > oscillator > > -Lasse
Ahh ok a simple RC oscillator on 20MHz ! mmhhh ... i would not experiment such a basic thing when stable, cheap and reliable integrated oscillators exits for years with a jitter as low as 1ps. Thank anyway, Habib.
On Sun, 03 Mar 2013 00:15:03 +0100, Habib Bouaziz-Viallet
<h.bouazizviallet@free.fr> wrote:

>On 03/03/2013 00:09, langwadt@fonz.dk wrote: >> A 74HCU04,an xtal, 2 caps, 2 resistors and you have a very nice >> oscillator >> >> -Lasse > >Ahh ok a simple RC oscillator on 20MHz ! mmhhh ... i would not >experiment such a basic thing when stable, cheap and reliable integrated >oscillators exits for years with a jitter as low as 1ps. > >Thank anyway, Habib.
Habib, Your debut if off to a very shaky start. Most of the world uses 74HCU04 as the core of their crystal oscillators. And those two-pin ports on Microchip's uP's... guess what's inside ?:-) ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
On Sun, 03 Mar 2013 00:04:25 +0100, Habib Bouaziz-Viallet
<h.bouazizviallet@free.fr> wrote:

>On 01/03/2013 18:07, Jim Thompson wrote: >> You can easily slap one together with a 74HCU04. Just make sure it's >> the "U" version. >Hello Jim, > >What do you mean with "slap together with a U version" ? I believe an >integrated oscillator will not gain benefit with an additional U version >of anything. > >Best regards, Habib
You're clueless... with a mouth to match :-( ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
On Sun, 03 Mar 2013 00:11:12 +0100, Habib Bouaziz-Viallet
<h.bouazizviallet@free.fr> wrote:

>On 01/03/2013 18:48, Spehro Pefhany wrote: >> Conner-Winfield DV75C series has maximum integrated phase jitter 1ps >> RMS over 12kHz to 20MHz > >Really good point, thank you. But for the silabs solutions i think these >guys are too obfuscated ... and i'm too in a hurry. > >Best Regards, Habib.
You're French... what can you say ?>:-} ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
On Mar 3, 12:15=A0am, Habib Bouaziz-Viallet <h.bouazizvial...@free.fr>
wrote:
> On 03/03/2013 00:09, langw...@fonz.dk wrote: > > > A 74HCU04,an xtal, 2 caps, 2 resistors and you have a very nice > > oscillator > > > -Lasse > > Ahh ok a simple RC oscillator on 20MHz ! mmhhh ... i would not > experiment such a basic thing when stable, cheap and reliable integrated > oscillators exits for years with a jitter as low as 1ps. > > Thank anyway, Habib.
not an RC oscillator a crystal oscillator, the R's are for bias and drive the C's for the xtal -Lasse
On 03/03/2013 00:21, Jim Thompson wrote:
> On Sun, 03 Mar 2013 00:11:12 +0100, Habib Bouaziz-Viallet > <h.bouazizviallet@free.fr> wrote: > >> On 01/03/2013 18:48, Spehro Pefhany wrote: >>> Conner-Winfield DV75C series has maximum integrated phase jitter 1ps >>> RMS over 12kHz to 20MHz >> >> Really good point, thank you. But for the silabs solutions i think these >> guys are too obfuscated ... and i'm too in a hurry. >> >> Best Regards, Habib. > > You're French... what can you say ?>:-} > > ...Jim Thompson >
Jim, I will never experiment a RC or Quartz + 74HCU or anything like that to achieve a low jitter oscillator. I leave this sort of thing to some flashers beginners. No offense. And the fact is i'm French has nothing to do with this. Habib.