smallest 0603 cap

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
 
> I'm actually working on a proof-of-concept that needs two separate TIAs 
> to have very closely similar phase and amplitude response out to a 
> couple of hundred kilohertz, which requires excellent phase matching. 
> We're only making 10 or so boards, so I'm planning to put a couple of 
> DNP caps in parallel with the main one, to get the tolerance down from 
> ~5% to ~0.5%.  (Yes, this will require a bit of measurement and 
> selection on each board, but there aren't very many, and we have all the 
> stuff in stock.)
> 

Did you look at parts  similar to
https://www.mouser.de/c/passive-components/capacitors/silicon-rf-capacitors-thin-film/?q=0402%201pf

At least you do not start with 5 %.

Bye
-- 
Uwe Bonnes                bon@elektron.ikp.physik.tu-darmstadt.de

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
--------- Tel. 06151 1623569 ------- Fax. 06151 1623305 ---------

On 26 Jan 2023 19:06:59 GMT, Uwe Bonnes
<bon@hertz.ikp.physik.tu-darmstadt.de> wrote:

>Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
> 
>> I'm actually working on a proof-of-concept that needs two separate TIAs 
>> to have very closely similar phase and amplitude response out to a 
>> couple of hundred kilohertz, which requires excellent phase matching. 
>> We're only making 10 or so boards, so I'm planning to put a couple of 
>> DNP caps in parallel with the main one, to get the tolerance down from 
>> ~5% to ~0.5%.  (Yes, this will require a bit of measurement and 
>> selection on each board, but there aren't very many, and we have all the 
>> stuff in stock.)
>> 
>
>Did you look at parts  similar to
>https://www.mouser.de/c/passive-components/capacitors/silicon-rf-capacitors-thin-film/?q=0402%201pf
>
>At least you do not start with 5 %.
>
>Bye

Check out

PEREGRINE  PE64907MLAA-Z

We use them for coarse-tuning an LC oscillator which is then
fine-tuned over a small range by a varicap.

It replaced a Maxim part that of course went EOL.

Uwe Bonnes wrote:
> Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
>   
>> I'm actually working on a proof-of-concept that needs two separate TIAs
>> to have very closely similar phase and amplitude response out to a
>> couple of hundred kilohertz, which requires excellent phase matching.
>> We're only making 10 or so boards, so I'm planning to put a couple of
>> DNP caps in parallel with the main one, to get the tolerance down from
>> ~5% to ~0.5%.  (Yes, this will require a bit of measurement and
>> selection on each board, but there aren't very many, and we have all the
>> stuff in stock.)
>>
> 
> Did you look at parts  similar to
> https://www.mouser.de/c/passive-components/capacitors/silicon-rf-capacitors-thin-film/?q=0402%201pf
> 
> At least you do not start with 5 %.
> 
> Bye
> 

Thanks, Uwe,

Very nice.  I confess that I wasn't aware of the whole precision 
picofarad capacitor niche--I can get 100 pF 1% NP0s for two cents in 
hundreds, hurrah.

Cheers

Phil Hobbs

-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

Get your xacto knife & slice across a trace on the pc board.

Hul

John Larkin <jlarkin@highlandsnipmetechnology.com> wrote:
> I need a tiny cap.

> This one is interesting

> https://www.mouser.com/ProductDetail/Walsin/RF03N0R1B100CT?qs=sGAEpiMZZMvsSlwiRhF8qtsBU8Zhqm2Ra%2Fa5698GTEQZP2uSIBTS%2FQ%3D%3D

> Below 0.1 pF, maybe I can use a 10 meg resistor, which is around 0.04
> pF. Maybe a couple in series? Maybe a network?

On Fri, 27 Jan 2023 16:56:47 -0000 (UTC), Hul Tytus <ht@panix.com>
wrote:

>Get your xacto knife & slice across a trace on the pc board.
>
>Hul

That's not very manufacturable.

On Friday, January 27, 2023 at 9:26:34 AM UTC-8, John Larkin wrote:
> On Fri, 27 Jan 2023 16:56:47 -0000 (UTC), Hul Tytus <h...@panix.com> 
> wrote:
> >Get your xacto knife & slice across a trace on the pc board. 

> That's not very manufacturable.

Unknowable.   Do you recall turret tuners, where each of  a dozen channels'
LC time constants were adjusted, in several  places per channel,
in mass production?   That started out with handwork, but got
automated, and... was actually pretty efficient.

Someone got clever and put an array of computer-controlled pistons
to work squishing coils until they hit the target value.

The 'slice across' could be laser scan, or vibrating chisel, or 
platinum-spark-plug electrode doing spark erosion, if you want
a manufacturable process.  Maybe just a grinding wheel
and a jig to present the right edge to the right feed depth,
about as fast as applying an inspection stamp.

On Thursday, January 26, 2023 at 11:07:06 AM UTC-8, Uwe Bonnes wrote:
> Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote: 
> 
> > I'm actually working on a proof-of-concept that needs two separate TIAs 
> > to have very closely similar phase and amplitude response out to a 
> > couple of hundred kilohertz, which requires excellent phase matching. 
> > We're only making 10 or so boards, so I'm planning to put a couple of 
> > DNP caps in parallel with the main one, to get the tolerance down from 
> > ~5% to ~0.5%. (Yes, this will require a bit of measurement and 
> > selection on each board, but there aren't very many, and we have all the 
> > stuff in stock.) 
> >
> Did you look at parts similar to 
> https://www.mouser.de/c/passive-components/capacitors/silicon-rf-capacitors-thin-film/?q=0402%201pf 
> 
> At least you do not start with 5 %. 

You beat me to it. It can be had with 10 fF tolerance. They are very repeatable. There is nothing quite like Accu-P. They can get expensive with the tight tolerance. 

On Saturday, January 28, 2023 at 11:21:47 PM UTC-4, Simon S Aysdie wrote:
> On Thursday, January 26, 2023 at 11:07:06 AM UTC-8, Uwe Bonnes wrote: 
> > Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote: 
> > 
> > > I'm actually working on a proof-of-concept that needs two separate TIAs 
> > > to have very closely similar phase and amplitude response out to a 
> > > couple of hundred kilohertz, which requires excellent phase matching. 
> > > We're only making 10 or so boards, so I'm planning to put a couple of 
> > > DNP caps in parallel with the main one, to get the tolerance down from 
> > > ~5% to ~0.5%. (Yes, this will require a bit of measurement and 
> > > selection on each board, but there aren't very many, and we have all the 
> > > stuff in stock.) 
> > > 
> > Did you look at parts similar to 
> > https://www.mouser.de/c/passive-components/capacitors/silicon-rf-capacitors-thin-film/?q=0402%201pf 
> > 
> > At least you do not start with 5 %.
> You beat me to it. It can be had with 10 fF tolerance. They are very repeatable. There is nothing quite like Accu-P. They can get expensive with the tight tolerance.

That was a trip.  Accessing the German Mouser site from Puerto Rico.  My choices are German or Spanish... I think! 

-- 

Rick C.

-+ Get 1,000 miles of free Supercharging
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