Quick update on the YTO/YTF driver board – with 16 bits of resolution. Assembly, is complete, and basic function has been checked – digital control test will follow tomorrow.
Current is settable from 0 to 250 mA, with 65535 counts of resolution – about 3.8 Microamps per LSB. All has been build to minimize noise, with heavy filtering on the supplies. The DAC is run from a dedicated 5 V supply, with a 2.5 V precision reference, 1 ppm/K, MAX6325ESA+.
The U to I converter is powered by 11.4 V – provided by a LM317 voltage regulator.
Switching element is an IRF730, operated as a series variable resistance in series with the coil.
Looking at the BoM, the parts sum up to about USD 35 plus board, not bad – target is to stay below about $100 for the final assembled unit, which will be achievable, no issue. Main cost comes from the MAX reference, and the DACs (DAC8830), almost USD 22.
To come: bandwidth testing
Hi,
Why are you using 2 DACs?
Cheers,
José
There is a simple reason, I had to control mulitple yigs. You will need,only one dac per yig.
Hi,
Thank you for your promptly reply, I’m planning on using your circuit as a 2-18GHz Yig filter driver although I will need over 1A for full swing.
Thank you!
Hi,
Thank you for your promptly reply. I’m planning to use your circuit to drive a 2-18GHz YIG filter, however I’ll need to handle the 1A tunning coil current needed for full swing.
Thanks,
José
Just be sure to use a very stable and sufficiently cooled current sense resistor. Otherwise, you get a lot of frequency drift. I am using dale rh series, important to look for low temperature coefficient.