RF transistor/amplifier ID - Page 1
Forum section: electronics / rf-microwave

author: DaJMasta
author_rank: Super Contributor
timestamp: December 28, 2017, 06:23:49 am
content: Working on a repair project (LeCroy WavePro 7200 timing board) and have two RF packages I've been unable to track down part numbers for - there are quite a few in the path and it's looking like at least one is going to need to be replaced.Both are 4 pin SMD packages of a familiar shape, the white package is probably ceramic (sounds different when bumped with the tweezers), but the markings are cryptic. _1 for the first black plastic amp (two of them are the first two stages in the path), then S1 for the white ceramic packages of which there are several stages and then a few as a distribution amplifier at the end. The VCO feeding the first stages tops out at 3GHz, and hooked up to the SA, both probing the VCO output, the amplifier stages, and hooked directly to the output of the board I'm seeing 2.43GHz and its second harmonic, so I figure the amps could be good up to about 5GHz (one other transistor I've ID'd near the VCO is rated to 5GHz.Ideas on what the parts are or a good place to go looking? The markings seem so generic that almost everything comes up in a simple google (especially S1 when searching for RF related stuff...), and I haven't been able to find another reference to the board or trying to repair it.

author: phenol
author_rank: Regular Contributor
timestamp: December 28, 2017, 07:12:10 am
content: The black mmic looks like ERA-1, the other one go figure...

author: David Hess
author_rank: Super Contributor
timestamp: December 28, 2017, 12:31:43 pm
content: They look like MMIC amplifiers from Mini-Circuits which is consistent with the output networks.

author: PartialDischarge
author_rank: Super Contributor
timestamp: December 28, 2017, 12:51:27 pm
content: Long time ago I also had to decipher one of this 4 legged amps. Eventually it was an old HP, now avago, from the MSA-xxx series. From what I learned I'd recommend you to identify the exact package and narrow from there, there are many, they seem similar, but they are not. You've got the 05 plastic package, the 86...

author: David Hess
author_rank: Super Contributor
timestamp: December 28, 2017, 01:38:24 pm
content: Quote from: MasterTech on December 28, 2017, 12:51:27 pmAnd now Broadcom. I am waiting for them to put all of the Avago datasheets under a NDA and charge for parts based on application to prevent freeloaders from using mixer diodes in sampling applications.Haha, I just checked and Broadcom announced this month that they are discontinuing practically everything Avago made. Well, so much for that.Who else produces microwave schottky mixer diodes?

author: DaJMasta
author_rank: Super Contributor
timestamp: December 28, 2017, 05:10:38 pm
content: Quote from: phenol on December 28, 2017, 07:12:10 amI think it's likely, though maybe the ERA-1SM variant because of the extra bend in the legs. Looked through the datasheet and the biasing resistor is exactly what they recommend (137 ohms for 9V of biasing), the regulator supplying the bias is set to 9.2V, which should work out to about 3 ohms of DC resistance in the inductor, which seems about right. The bandwidth would also be a match and the VCO itself is also minicircuits.Still not totally sure about the ceramic package one, the package does seem to be slightly smaller and straight legged, the current minicircuits lineup doesn't list any part numbers that contain "S1" and don't show any of this style ceramic packages... but it's old, I'll have to sift through some previous models.

author: rfeecs
author_rank: Frequent Contributor
timestamp: December 28, 2017, 05:50:14 pm
content: Googling "ceramic mmic S1" yields this one:Sirenza SNA-176http://rfelektronik.se/manuals/Datasheets/sna-176.pdfSirenza is gone now, acquired by RFMD, then merged with TriQuint to form Qorvo.

author: DaJMasta
author_rank: Super Contributor
timestamp: December 28, 2017, 06:27:52 pm
content: I think that's it! Looks like I'm not the only one with the google-fu issue, though, without the "MMIC" it seems tough to find. (same story herehttps://www.eevblog.com/forum/testgear/teardown-repair-analysis-of-an-agilent-e4443a-3hz-6-7ghz-spectrum-analyzer/)Anyways, while the biasing resistor on the first one in the chain is too high for the recommendation on the datasheet, the remainder of the ones later in the path are using 105 ohm bias resistors, which is right in line with what I'd expect for 9V. Odd though, my last repair also involved replacing some Sirenza amplifier parts.... I guess they're popular, at least.

author: David Hess
author_rank: Super Contributor
timestamp: December 29, 2017, 03:25:15 am
content: Quote from: evb149 on December 29, 2017, 03:07:02 amI found no lack of alternatives but none as good as the Avago parts. Unfortunately using them means starting over with qualifications.QuoteI wondered if Broadcom bought Avago to compromise a competitor. Now I think that was the case.

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: December 29, 2017, 06:42:20 pm
content: Quote from: David Hess on December 29, 2017, 03:25:15 amI also see a pattern here. Specifically, that components are discontinued which did sell and which were not problematic to produce, so that they should be kept in the portfolio if there wasn't a hidden agenda.If nobody is selling the basic components to make up new circuitry, all innovation outside of the semiconductor manufacturers is stifled. Combined with the fact that they handle their product lines like if there is no responsibility of any sort, one might think that a lot of totally unneccessary redesigns occur.

author: rfeecs
author_rank: Frequent Contributor
timestamp: December 29, 2017, 08:50:02 pm
content: Quote from: David Hess on December 29, 2017, 03:25:15 amActually, Avago bought Broadcom. They changed their name from Avago to Broadcom Limited. They did not have competing product lines.

author: David Hess
author_rank: Super Contributor
timestamp: December 30, 2017, 12:28:31 am
content: Quote from: rfeecs on December 29, 2017, 08:50:02 pmWho bought who doesn't actually matter and I wasn't talking about them competing with themselves. If they have other competitors with Broadcom who were relying on Avago's products for support, then it makes sense to discontinue those Avago products. Usually I see it where one of two competitors buys a company that the other is relying on either directly or through their customers encouraging their customers to switch.Anyway, it was not as much of a problem as I suspected it would be and I now have a handful of substitutes for everything I was using from Avago. Broadcom is not a problem because I hate their products.