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eBay seller edgartech. They said they heard it could be a TI SN74AUC2G125 (most likely based on this http://www.digikey.com/product-detail/en/SN74AUC2G125YZPR/296-16800-1-ND/634960). This looks more like a power diode but I'm marking it TI since I have nothing better and it does say TI on the label.
Markings
SLICE No. 32 WAFER TYPE TU155YQ LOT NUMBER 0185737 TI Part No 16800-1 GOOD QUANTITY 1205 UK ORIGIN