Tool/software:
Hi,
I am trying to use this TPS7A39 LDO voltage regulator for my design to power 250mA load. The first page on this datasheet it shows 150mA is the output current but in Electrical Characteristics table it shows current limit 300mA+ for typical while showing the max is actually 500mA. I am confused. My question is: can this LDO provide 250mA output current for my application ? I am dropping 1V across this LDO.
Hi Jak,
Thank you for asking! The part is rated for 150mA, which means that each channel will always be able to source 150mA of current and remain within spec while doing so. However, the device doesn't begin to limit its own current until outside that range. The exact point at which the transition to current limit begins is defined by the max current spec. That point must be within 200mA-500mA, and was measured on the bench on a number of parts to be 330mA on average. In my own experience, that point exhibits some dependence on temperature and VIN. To note: the recommended operating range only goes up to 150mA, and anything outside of that will not necessarily meet other performance specs even if the device is properly regulating.
The answer your question directly: The device is likely able to source 250mA in many conditions but is not guaranteed to do anything above 200mA, and you lose the EC table spec guarantee past 150mA.
See the below curve for a real part's current limit across temperature, with VIN=3 and VOUT=1.188 (which will likely be reflective of your performance in your conditions):
Best,
Gregory Thompson
