I think I was being dumb when designing my circuit board that would be the carrier for the Teensy 4.1. Since all my extra circuitry would be running off 3.3V and I was worried that the 250mA of the onboard voltage regulator wouldn't be enough, I instead was just going to use a 3.3V offboard supply coming in to a connector to power my external circuitry and the Teensy. However, looking at the schematic for the Teensy 4.1 (https://www.pjrc.com/teensy/schematic.html) which my idiot self is kicking myself for not having done more scrupulously before having the boards made, it appears that I **have to** have 5V either from USB or external.
Is this correct?
If so, I think I may be able to salvage this board (I am only populating 4 of them for a consulting job). So, I think I could run in 5V on the power pin instead of 3.3V, cut the trace from the connector pin to the Teensy 4.1 3.3V pin, then cut the 5V USB pad-to-pad trace, and direct solder from the connector pin or positive lead of the throughhole decoupling cap to the one side of the 5V USB pad-to-pad pads or 5V pin. I think that in the end I will be under the 250mA total (by about half).
Does this sound like reasonable as a fix?
Is this correct?
If so, I think I may be able to salvage this board (I am only populating 4 of them for a consulting job). So, I think I could run in 5V on the power pin instead of 3.3V, cut the trace from the connector pin to the Teensy 4.1 3.3V pin, then cut the 5V USB pad-to-pad trace, and direct solder from the connector pin or positive lead of the throughhole decoupling cap to the one side of the 5V USB pad-to-pad pads or 5V pin. I think that in the end I will be under the 250mA total (by about half).
Does this sound like reasonable as a fix?