TIDA-00176: Unknown voltage in schematic

Hello Mathijs,

thank you for your interest in the TIDA-00176 TI designs. To your question: The V_dc1, like the V_dc2 are the 3.3V supply inputs for the analog comparators TLV3202 U9 and U15 respectively. To avoid that switching noise from the comparator supply rails couples into the 3.3V supply plane (V_3_3_dc) we use for the analog Sin/Cos amplifiers too, we decouple each of the TLV3202 supplies with an RC filter such as R42 (1 Ohm), C49 (100nF) for U9 and R73, C74 for U15. We added a label each V_dc1 and V_dc2 to make it more visible.

We explain this briefly in the TIDA-00176 design guide (TIDUA05A), page 25:
"The 3.3-V supply of each comparator is decoupled with a 1-Ω series resistors and 100-nF capacitor to minimize cross-talk through the 3.3-V rail to other comparators."

We could have added V_dc1 and V_dc2 in the design guide to reference to the label in the schematics.
I hope the more detailed answer above clarifies your question.

Regards,
Martin Staebler