Were you looking for the Analog Devices Forum ? 

No - because I didn't know that there was one !

I do now - thanks.

It's hard to find fora because they are listed in different places - following your prompt I found "Analog Devices" in the Manufacturers (under Products).

Is there a way to get a list of ALL the existing fora ?

But ideally I wanted an Analogue Design forum  - or close to that - the point of the post is to inform people who do chip level analogue design, rather than have a passion for ADI themselves.

I very nearly put it in "Embedded" .

MK

I had to look up DigiTrim. Despite AD claims that it is a lower cost process than zener zapping or chopper stabilization, the part costs don't seem to reflect this. However they are nice parts.

Hi Michael,

Great selection! I saw that ADL5960 chip recently, and I couldn't tell if it would be good or not, the dev-board outputs two IF signals in analog form, and to extract the performance would either need more processing in the analog/frequency domain (e.g. down-convert to zero IF) and then LPF and then sample it, or would need to be sampled at the IF and then process it, to get the gain and phase magnitudes. The software to control/measure/compute would be a lot of work, but there is open source (e.g. LibreVNA PC application) that could perhaps be a base from which to start. Also, there's no frequency generation on the eval board, so that would be needed (for both the measurement frequency sweep and for the LO). The chip/dev-board could be a very attractive way to create an embedded VNA for scientific instruments or a more general instrument could be made with a couple of the boards for 2-port. Unfortunately, the 10 MHz limitation is because a key part of the circuit is fully integrated into the chip, which is an excellent thing for size and performance at high frequencies but doesn't scale to the lower frequencies.

MiniCircuits released (a couple of years ago) a VNA based on their parts, as a sort of 'training' VNA, but it was very expensive, $10k or so). It would be nice if AD could find a way to offer something ready-made much like the ADALM-PLUTO, at a lower cost, perhaps deliberately reduced to 3 GHz, so that it doesn't eat into sales of their 20 GHz product at the full price.

The affordable option that's tempted me for a while is VNWA 3EC (£259+tax), which has the main problem that it only supports up to 1.3 GHz, but other than that, the specs are good, and the PC software is quite functional although the menu structure is very unintuitive. The VNWA has the advantage of working from 1 kHz upwards! Dynamic range is good (not excellent) and reduces into VHF and beyond, but at that price, it's a completely usable 2-port VNA. And, because it's been around for ages, most bugs are ironed out, so there'd be little doubt at the measurements it provides. One quite interesting feature is that it's possible to extend the impedance range (into milliohm and up to 100s of kohm) using a neat add-on circuit called RF-IV, turning the system into a really good general impedance meter. I've built that circuit for a DIY 'N2PK' VNA (which only works to 60 MHz, so that's quite a restriction), but that RF-IV circuit functions to a GHz or so apparently, and is compatible with the VNWA. I *think* the circuit is patented, which is why there's no commercial product (other than high-end Keysight instruments) that offers it, but fortunately, it was easy to DIY. The N2PK VNA has an extremely good dynamic range (better than some commercial VNAs), so for impedance measurements from 50 kHz to 60 MHz, it's exceptionally good. Hopefully VNWA would be good too.

Really impressive specs on those ADG switches! The MAX chip looks nice too. A while back I was looking at using TI LM5050 chips, which are cheaper but need external MOSFETs, for OR'ing a couple of supplies, but in the end that particular requirement went away.

"Is there a way to get a list of ALL the existing fora ?"

Almost all groups have a forum, someone in their infinite wisdom when we moved to Verint, decided to name all of the forum applications "Forum", so you have to go by the group name.

"But ideally I wanted an Analogue Design forum  - or close to that - the point of the post is to inform people who do chip level analogue design, rather than have a passion for ADI themselves."

Okay, I'm happy to create a dedicated forum for that, but hmm, you may be onto something that there might not be a good fit somewhere for it at the moment? I had a look through  Technologies and there are the groups listed on /sitemap - maybe renaming 'embedded' or another group to something close to suitable could accommodate a forum dedicated to this?

Thanks Chris,

Extending Embedded and Microcontrollers by the addition of Analogue Design would work fine for me.

It has sub fora of Embedded, DSP and PIC Microcontrollers so adding an Analogue Design forum to that set would be reasonable.

Designing complete embedded systems almost always involves some analogue, if only in the power supply si it makes some sense to bundle them together.

MK

I took a quick look at the VNWA - looks very interesting.

But I must resist rushing out to buy one since I have about a dozen Rabbits on the go right now. (Rabbits are side jobs without paying customers.)

MK

 Analogue Design  - would you like me to convert and move this post over?

Same here, it's a nice-to-have but in the back of my mind for if/when the need arises.

The time cost adds up too! Bit of a learning curve with tools/software too, that can chew up days : ( I purchased a new logic analyzer recently, need to learn that (hoping it won't take as long, I tried out the software before purchasing).

Yes please - nice to be the first post !

MK