Current consumption by a LDO (5v to 3.3v)


There is a LDO that converts 5v to 3.3v and has a quiescent current of 0.11mA. Suppose it powers a ultra low power digital sensor (i2c or spi based) that uses only 50uA, (there is an mcu too but that runs on 5V, the sensor's data lines are 5v tolerant but not the power lines) Then what will be current through the LDO, will it be in mA or uA ??

Best Answer

It should be close to 160uA but check the datasheet to be sure (it might draw more current for its own use depending on the output current, but this is rarely significant except when the input voltage approaches to output voltage, and then only for bipolar regulators).

If it is mA (as in several mA) then almost certainly something is wrong.