Long time lurker, first time post.
I'm repairing a Lenovo Yoga 2 11. As is fairly common, it lost a FET in the charging circuit. It'd run off battery (til that went flat) then gave all the signs of a brick. Juice the battery, and it runs some more. Charge controller thinks it's charging, but no current flows. Already performed this repair a couple of times on different laptops.
I have identified the faulty FET, a
NTTFS4C25N, and for the sake of testing dropped an
AON7408 in place and observed the expected voltage rise on the battery side. Used
this testing procedure, it seems to be failed shorted Drain to Source. The FET in question seems to be an intermediate step after the FET that takes 20V in from the AC adapter.
Here's a bad picture. PQ202 is the FET in question.
Now, the question: I have a number of other FETs available, but not an exact match. I just don't know enough about DC-DC converters to accurately assess if any of them might be a suitable (long term) replacement. I could source the correct replacement from mouser without much issue, so I'm mainly curious. And a little lazy. The AON7400 seems to be reasonably close, but there's some parameters on the datasheets I just don't know about. Charge controller is a
BQ24715.
Here's what I've got:
AON7400AON7408AON7516TPCA8065Thanks in advance for any useful info.