YTO YTF Driver: 0..250 mA, 16 bits resolution

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.

YTO YTF driver 2x250 mA 16 bit

YTO YTF driver 2x250 mA 16 bit schematic

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

5 thoughts on “YTO YTF Driver: 0..250 mA, 16 bits resolution”

      1. 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!

      2. 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

        1. 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.

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