eclips oscillator

On Mon, 7 Feb 2022 23:07:06 -0800 (PST), whit3rd <whit3rd@gmail.com>
wrote:

>On Monday, February 7, 2022 at 6:56:15 PM UTC-8, jla...@highlandsniptechnology.com wrote:
>
>> This should work. 
>> 
>> https://www.dropbox.com/s/chgyy2kvj6ye5gq/Osc_EP11_LC1.jpg?raw=1
>
>Substituting a tapped inductor (drive the tap, sense/resonate the endpoint) would improve
>the slew rate.   Tapped inductor is a gain boost, and the chip has input clamps.

That chip has lots of gain, and we have lots of low-nH 0603 inductors
in stock. 



-- 

I yam what I yam - Popeye

On Wednesday, February 9, 2022 at 12:25:02 AM UTC+11, jla...@highlandsniptechnology.com wrote:
> On Mon, 7 Feb 2022 23:07:06 -0800 (PST), whit3rd <whi...@gmail.com> 
> wrote:
> >On Monday, February 7, 2022 at 6:56:15 PM UTC-8, jla...@highlandsniptechnology.com wrote: 
> > 
> >> This should work. 
> >> 
> >> https://www.dropbox.com/s/chgyy2kvj6ye5gq/Osc_EP11_LC1.jpg?raw=1 
> > 
> >Substituting a tapped inductor (drive the tap, sense/resonate the endpoint) would improve 
> >the slew rate. Tapped inductor is a gain boost, and the chip has input clamps.
>. 
> That chip has lots of gain, and we have lots of low-nH 0603 inductors 
> in stock.

Not all that much gain at 1.5 GHz.

And you don't seem to know enough about how your SMD inductors  work. Most of the ones I used printed a straight conducting track onto a lump of ferrite.

Getting much magnetic coupling between them might be difficult. Ferrite beads don't look as neat, but at least you know exactly the route the current follows.

-- 
Bill Sloman, Sydney

On Saturday, February 5, 2022 at 12:38:04 AM UTC+11, John Larkin wrote:
> On Wed, 02 Feb 2022 08:53:27 -0800, jla...@highlandsniptechnology.com 
> wrote:
> >https://www.dropbox.com/s/627ifxuw3rsexj2/EP11_Oscillator.jpg?raw=1 
> > 
> >Wonder how that will work. I'll have one of my people try it.
>
> Oscillates at 1.5 GHz, reasonable square wave, bad tempco. 
> 
> Can be tuned down maybe 20% with C2. 

This is a pretty silly post. The MC10EP11 has a typical propagation delay of 220psec at room temperature - rising from  200psec at -40C to 240psec at 85C.

If what John is setting up is a delay line oscillator which relies on getting a total round trip delay of 333psec - 180 degrees of phase shift at 1.5 GHz - his "delay line" is contributing 113psec of that delay. At  -40C, the EP11 propagation delay would deliver 1.6GHz if the external delay remained the same, and at 85C it would deliver 1.42GHz.

113psec is good for about a 3.3cm propagation distance in free space, maybe 2.4 cm through printed circuit substrate.

The schematic he has posted doesn't seem to have been drawn with that in mind. What his mental model of his oscillator actually might be is something of a mystery - perhaps more of a mystery to him than the rest of us.

-- 
Bill Sloman, Sydney