[time-nuts] Adding prescaler to HP 5334B

[Didier Juges]

I was thinking of buying a few dual shottkys (series configuration) in
SOT-23 package and I thought it would be a piece of cake finding those, but
interestingly, my usual part vendors (Digikey, Mouser, Newark, Allied) don't
carry any that I could use, at least if they do, I did not find them. 

Anyone has recommendations for such an animal?

Didier KO4BB

> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Bruce Griffiths
> Sent: Monday, March 31, 2008 8:37 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Adding prescaler to HP 5334B
> 
> Bruce Griffiths wrote:
> > Robert Berg wrote:
> >   
> >> Having seen it discussed, I was wondering whether anyone 
> has actually 
> >> added the Schottky diodes and prescaler chip to a 5334B to 
> provide a 
> >> C-channel input. The matched Schottky quads (5082-2831) 
> are no longer 
> >> available, and even the recommended replacements (5082-2303) seem 
> >> scarce.  Was thinking of trying 1N5711s, which can be obtained as 
> >> matched sets, although probably not on my budget. How 
> critical is the 
> >> need to use matched sets? The NEC UPB1507GV-ACT-ND looks promising 
> >> for the prescaler, if the small form factor isn't too 
> minute to handle.
> >>
> >> Bob
> >> WA7ZRX
> >>   
> >>     
> > Not particularly critical as they are only used as clamps 
> to limit the 
> > input signal to the 30dB gain preamplifier.
> > You may be able to use a single pair instead, albeit with a lower 
> > input damage level.
> > Using a quad allows the clamp current to be shared between 
> a pair of 
> > diodes, however some matching is required to ensure 
> effective current 
> > sharing.
> > Too much diode shunt capacitance will limit the bandwidth.
> >
> > Bruce
> >   
> Quad CR303 acts as a clamp, Quad CR302 acts as a detector 
> with temperature compensation.
> Only 2 diodes in CR302 are used so CR302 can be replaced by a 
> matched pair.
> 
> Try using low barrier microwave specified schottky diodes 
> with lower capacitance than a 1N5711.
> 
> Bruce
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, 
> go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 
> Internal Virus Database is out-of-date.
> Checked by AVG. 
> Version: 7.5.519 / Virus Database: 269.21.8/1339 - Release 
> Date: 3/22/2008 4:43 PM
>  
> 

Internal Virus Database is out-of-date.
Checked by AVG. 
Version: 7.5.519 / Virus Database: 269.21.8/1339 - Release Date: 3/22/2008
4:43 PM