Electronics > RF, Microwave, Ham Radio

AD831 Chinese Mixer Module Questions And Answers

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Quarlo Klobrigney:
Before I hook this up, can anyone tell me the specs of these modules from sources such as Aliexpress and eBay https://www.ebay.com/itm/0-1-500MHz-High-Frequency-AD831-RF-Mixer-Drive-Amplifier-Module-Radio-Converter/153996768961 ? [attach=1]
I see really no info except for the raw IC in the AD datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/AD831.pdf
It specifies a LO and RF input without max input specs.
A supply voltage of: Dual supply ±4.5V-±5.5V or Single supply 9V-11V

So if anybody has used this module do you have any recommended parameters?

EXTRA: From a CERN paper page 44, 5.2.3 AD831 active mixer: "optimal LO drive level is -10 dBm. However, increasing the LO level to 0 dBm results in lowering the unwanted spectral components" Who knows, it's a paper by the people who want to suck us into a black hole...

Quarlo Klobrigney:
I still, after searching all day for anybody using this module and found that all of the suppliers have comments like "Works great! just what I was looking for" and "This really helped me on my design" and the rest....

One guy on the tube says 5V, another one on there 9V and so on, No definitive answers on what voltage or max input levels to apply. Although their projects work, they are from other countries and don't speak English and offer no wiring diagram help.... :-//

Anybody in the other hemisphere awake and reading this can help, I'd appreciate your help. I have to tell the vendor soon that it either works or get money back for a defective product. Thanks.

vk4ffab:
The datasheet is pretty clear. What specificaly dont you undrstand.i will answer your questions. I have the modules here and have used them

https://robs-blog.net/2020/03/02/ad831-mixer-module/

_Wim_:
From the PCB picture I see that pin 4 and 5 are tied to GND, so VN (negative voltage) is at GND. This means single supply operation. The pcb  "GND" and "Vcc" are directly connected to the AD831, so no local regulation or resistor divider. This means you have to power the board between 9V and 11V according to the datasheet. 10V is thus recommended.

Looking at the pcb, it seems they used pretty much the "single supply operation" schematic of the application note section of the datasheet (see attachment). The only differences I can spot are the input filtering, which is a single capacitor instead of C-L-C, and no low pas filtering is installed (82pF caps are omitted).

Using the attached schematic you can easily trace out if anything else is different, and when you are sure you have the complete schematic, read the appropriate sections of the AD831 datasheet to fully understand how you can use this. As said above, the AD831 datasheet should be quite clear. 

Quarlo Klobrigney:
Well I did power another module ordered in April initially at 5V and only one port would pass (forgot it it was the LO or RF). It was well below the datasheet max dBm level if you can believe the datasheet as it contradicts itself as to level input specs in a few places.
This is on a well regulated supply. I noticed that the AD831 IC was very warm, to which I found out that more than many are concerned about in other non answered postings, including an AD China site.
It then quit outputting anything. I then tried a 10V supply using a 7810 (I had a few) with good regulation and filtering but it still would not output anything.
The input was a signal generator knocked down by a pi attenuator to a proper a level on a scope somewhere around 60MHz.
I don't want to be accused of blowing this module up by the vendor. Vendors such as "weflowerbotique", "manythanksyou", who haven't a clue as to what they are selling.
I bought it instead of constructing a diode ring and associated torroids. I have used SBL-1's before and that was a very nice passive solution.
So now you can understand my apprehension to repeating failure.
If I could see one of these things working, it would alleviate such fear.

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