TPS51116-EP: Short between DRVH and LL pins

Hi Timothy,

The following line from the datasheet seems to suggest that the internal resistance between DRVH and LL is only 0.9 Ohms. For reference, how are you measuring the short in question?

Do all the ICs show this short measurement or only a select few of your stock?

Regards,

James

The device is unpowered and I am using a multimeter to measure the impedance between the pins.

I am assuming that there is some sort of depletion-mode FET for the high-side driver since there is no gate voltage on the output stage and a short is present.

Hi Timothy,

Edit: The LL current sense is handled separately in the control loop and doesn't appear to have a direct connection to the impedance with DRVH, but I wouldn't assume the short you are measuring indicates an issue with the IC unless other chips show drastically different measurements and IC performance is out of spec.

Also, based on the MOSFET symbol in this application diagram, it looks like the expected FETs are Enhancement Mode.

Regards,

James

James,

I am referring to the internal gate drive circuitry shown in the snippet from the block diagram below (not the external FETs you were alluding to).

I assume that the high-side FET drive circuitry has a depletion mode FET to hold off the gate-to-source voltage of the external high-side Buck FET, which is why I measure a short between these two pins.