in the DRV8824 datasheet on the block diagram in page 2, there is
a "VM" pin on the top left. That pin is not present on the table on
page 3 and on the pinout drawing on page 4. Is it correct to assume that
it is internally connected to both VMA and VMB?I built a test board and supplied 10V to both VMA and VMB, but I get nothing out of the internal 3V3 regulator.
Thank youBest regards
The reason your system is not coming up is because the VREG is being bootstrapped by the nSLEEP pin. This is a problem because VREG will only come up when nSLEEP is HI (device is not in SLEEP MODE). Hence, with the proposed system and at startup, the device will sit in SLEEP mode forever. My recomendation is to either pull up your nSLEEP externally or drive it with your microcontroller.
As a side note, VREG is only meant to drive the VREF analog input, and although it can supply up to 1 mA of current, it is not intended to be used as the LDO solution to drive the other device's logic inputs.
BTW, you have two pins mixed. Pin 14 is a ground, whereas pin 15 is V3P3OUT (the one you have called VREG).
Hope the info helps!
JIQJose I Quinones
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