Other Parts Discussed in Thread: SN65HVD230, INA240
Hello,
Accidently placed two resistor 90 degrees on +5v buck regulator, outputting +6.5v to LDO input. That passed +6.5v onto 3v3 bus immediately shorting VDD on TM4C1294KCPDTT3 MCU. After fixing buck regulator resistors it passed +5v to input of LDO, passing +3v3 to later and newly placed TM4C1294KCPDTI3.
How can +6.5v input to fixed +3v3 LDO output +6.5vdc after the MCU was removed? Oddly with shorted VDD the LDO output level was +3v3, immediately dropped to +2.09v via DMM check. Perhaps something in LDO was pulling the +5v buck down to +6.5v but how LDO output still remain +6.5v?
Absolute maximum input TPS735 is noted as 7.0v [SBVS087M –JUNE 2008–REVISED JUNE 2018]