TPS7A47-Q1: Will TPS7A47 has additional thermal protection against 36V->1.4V/Short scenario?

Hello Albert, 

This part has a brickwall current limit protection, explained here: 

https://e2e.ti.com/blogs_/b/powerhouse/posts/ldo-current-limit

Why is this device being shorted?

Thermal shutdown will protect the device if the power dissipation across the FET is too large. An instantaneous short may damage the device and so can prolonged use in thermal shutdown. 

Page 9 of this app note explains that the device may oscillate on and off to protect itself: https://www.ti.com/lit/eb/slyy151a/slyy151a.pdf

This app note explains how to calculate thermal performance and how to increase the package size to accommodate for large power dissipations: https://www.ti.com/lit/an/slva118a/slva118a.pdf

Updated thermal metrics: https://www.ti.com/lit/an/spra953c/spra953c.pdf

Best,

Juliette

Hello Albert, 

In high Vin scenarios, once the power dissipation across the device is too high, the LDO will turn off the output to cool the device down. once the device cools down, the LDO will turn on and begin regulating again. However, if the VIN is never dropped the output will continue to oscillate through thermal shutdown - long term usage in this stage will damage the device. 

In a short   scenario, the result is more unpredictable. The device may have the opportunity to shut itself off before damage is caused to the device but, depending on the extent to which abs max is violated, the device may be permanently damaged. 

Best,

Juliette