The component is supposed to be TCA9517DGKR, a level-shifting I2C bus repeater from Texas Instruments. I got these soldered from a turn-key Chinese fab. The top markings are TI43 (Or T143?) first line, and AYK second line:
The AYK is the correct chip mark for TCA9517. However the chip doesn't function as it should, whatsoever. When powered up as TCA9517, it clamps SDA and SCL lines. As a stand-alone, DMM shows no connectivity between any pins.
[The original (good) chip has a clear first-line mark as TI 6B]. More, the chip has some bottom thermal slug:
I suspect the chip is some medium-power transistor, but wasn't able to find a match. I have 250 of these suckers, and if someone can identify the chip, maybe I can re-use them in some other projects.
Best Answer
Possibly a TI audio amplifier chip.
Also bears the AYK marking (and has a thermal pad).
This may indeed be a procurement mistake. Perhaps you could share the specifics of the vendor just for general information.
P.S. Try the DMM on diode setting to check ICs. Chances are you will see something on every pin relative to GND, with the (+) probe on GND.