Bias voltage on ST1L08PUR

[markn]

Little confused by the spec of a max 90mV dropout while the Bias voltage needs to be >=1.5V higher than the regulated voltage.
So this regulator is only good in the case where that higher voltage is already present in the system?

https://www.st.com/content/ccc/resource/technical/document/datasheet/5f/25/d1/3f/f8/25/44/07/DM00123507.pdf/files/DM00123507.pdf/jcr:content/translations/en.DM00123507.pdf

[TDK]

> So this regulator is only good in the case where that higher voltage is already present in the system?

Yes. A 90mV max drop at 800mA is well above par. The tradeoff is that you need a higher voltage.

 

Plenty of general purpose LDOs out there if you don't have the higher voltage rail.