Source for step recovery diodes - Page 1
Forum section: electronics / rf-microwave

author: ezalys
author_rank: Frequent Contributor
timestamp: November 28, 2018, 03:01:42 am
content: Hey all,Does anyone have a good source for step recovery diodes? There are some on eBay from the ussr. Anyone used those? The packages are a bit funny. I’ve called a few manufacturers but they often have absurd minimum purchases per line item and no possibility to sample.E

author: David Hess
author_rank: Super Contributor
timestamp: November 28, 2018, 02:03:15 pm
content: Varactor diodes are constructed the same way and can be used as step recovery diodes. You will have to qualify them for your application but they are much more available.

author: 1sciguy
author_rank: Contributor
timestamp: November 29, 2018, 09:56:45 pm
content: Alone or in an rf package with SMA input and output? I have used them for gain-switching laser diodes, but then I learned they were unnecessary for gain switching a 50 ps pulse at 250 Mhz and higher. Not at work today, but I believe the company was microwave products. They definitely aren't cheap. >$500 each

author: Lukas
author_rank: Frequent Contributor
timestamp: November 29, 2018, 10:48:01 pm
content: Is 5GHz enough for you?http://www.macom.com/products/product-detail/MA144769-287T$2 a pop at Mouser.

author: David Hess
author_rank: Super Contributor
timestamp: December 02, 2018, 02:15:14 am
content: I see that Mouser has those listed under "Varactor Diodes".https://www.mouser.com/ProductDetail/MACOM/MA144769-287T?qs=%2fha2pyFaduhApqjh9HPp7LtS%252bumxE41Nu4ybChty6FpEM8BXZwZ01g%3d%3d

author: ezalys
author_rank: Frequent Contributor
timestamp: December 02, 2018, 10:45:30 pm
content: I've seen that part! I'm really looking for higher harmonics, though. What should one look for in a varactor for some confidence in it delivering higher harmonics, up to 12 ghz or so? I know I'd have to buy parts and characterize them, but if I were to look for 10 parts to characterize, what would I look for?

author: KE5FX
author_rank: Super Contributor
timestamp: December 03, 2018, 12:17:03 am
content: What's your application?

author: ezalys
author_rank: Frequent Contributor
timestamp: December 03, 2018, 01:13:00 am
content: Sampling detector

author: Wolfgang
author_rank: Super Contributor
timestamp: December 03, 2018, 06:00:14 pm
content: Hi,eBay has lots of packaged stuff (Herotek SMA parts) plus a real lot of former Soviet union stuff for very low prices.What is the recovery time you are looking for ?Wolfgang

author: ezalys
author_rank: Frequent Contributor
timestamp: December 04, 2018, 12:38:24 pm
content: I'll give the soviet ones a crack. I've used the soviet tunnel diodes and they're great. I just don't know how to work with this packagehttps://www.ebay.com/itm/2D524A-KD524A-Microwave-Step-Recovery-Diode-100GHz-Lot-of-10pcs/232822145434?hash=item363548019a:g:vscAAOSwbVNbMpgS:rk:4:pf:0. I know this is a somehow standard packaging... does anyone have any examples of how packages like this are used/mounted? I realize it ultimately doesn't matter for the frequencies I'm interested in... but I am curious.

author: Wolfgang
author_rank: Super Contributor
timestamp: December 04, 2018, 01:47:06 pm
content: The package in your link was mounted in a waveguide, with an isolated piston coming from above for bias.

author: ezalys
author_rank: Frequent Contributor
timestamp: December 04, 2018, 02:50:48 pm
content: Do you have any pictures? It seems like such a mounting setup would be most appropriate for generation of harmonics and not for a sampling gate.

author: Wolfgang
author_rank: Super Contributor
timestamp: December 04, 2018, 06:40:40 pm
content: The diodes used for sampling had the pill package with two striplines attached.

author: ezalys
author_rank: Frequent Contributor
timestamp: December 04, 2018, 06:43:17 pm
content: It seems that the diodes available on ebay are inappropriate then.

author: Wolfgang
author_rank: Super Contributor
timestamp: December 04, 2018, 06:49:29 pm
content: Why ? eBay has stripline and mini coaxial types.What frequency range do you have in mind ?What you could look at are the internals of the vintage Tektronix sampling heads. The manuals (on the web) have drawings how it was done. They used either tunnel or step recovery diodes to create the pulses, and very small caps to differentiate the rising edge. the edge pulse was used to drive the sampler diodes.