Re: 1S1 sampling bridge GaAs diodes: What alternatives?


Dave Wise
 

I replaced my 1S1's four sampling diodes with four HSMS-8202 dual diodes, with each part wired to use the two diodes in series to increase the breakdown voltage and reduce the capacitance.
They are marked Obsolete at the major distributors, but Quest Components appears to have a few, as do MiniKits in Australia. There are about a dozen auctions at eBay.

Today I would use the Macom MA4E2054B1-287T which they list as a direct cross-ref. They are in stock at DigiKey and Mouser.
Or the Infineon BAT15, BAT17, or BAT62.

HTH,
Dave Wise

These are SOT-23. I made a little T-shaped "chip carrier" out of bare PCB material that fits in the original clips.
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Jim Ford via groups.io <james.ford=cox.net@groups.io>
Sent: Wednesday, December 09, 2020 2:43 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 1S1 sampling bridge GaAs diodes: What alternatives?

Although discontinued by Avago/Broadcom, I'm sure. That's the way it
goes these days. They discontinued me and a whole lot of others as
well, as some of you are probably tired of hearing me say!

The HSMS-28XX and other former HP Semiconductor devices just don't have
the volume they once had, and the suits at Avago/Broadcom don't like
that, nor do their investors.

Jim Ford

------ Original Message ------
From: "Tom Lee" <tomlee@ee.stanford.edu>
To: "TekScopes@groups.io" <TekScopes@groups.io>
Sent: 12/9/2020 2:31:43 PM
Subject: Re: [TekScopes] 1S1 sampling bridge GaAs diodes: What
alternatives?

I have not actually fixed one this way, but I would expect an HSMS-28xx Schottky to be a perfect replacement here. These are readily available.

Tom

Sent from my iThing, so please forgive the terseness and typos.

On Dec 9, 2020, at 14:26, "leonard scheepsma" <tubes.leonard@hetnet.nl> wrote:

Dear all, my 1S1 gave up. It looks at least one of my sampling diodes has died. Searching through the related messages I noticed most comments are pretty old, so I hope some new ideas might have been launched on getting alternatives for the original GaAs diodes, just assuming these are completely unobtainable.
Looked at the Agilent/KeySight site, they mention some ultra fast GHz diodes there but these go through a distributor and I suspect ut won't be easy to get 4 of these at reasonable cost (not knowing they would work either)
Any tips, suggestions?

Thanks so much, Leonard







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