IEEE 1394a Three-Port Cable Transceiver/Arbiter
http://www.ti.com/product/tsb12lv26
Also contains a TSB12LV26 PCI-1394 bridge
Markings:
(TI) 18A5YCHT TSB41AB3
Size is approximately 2290 x 1850 μm (4.23 mm2)
Top left:
TSB41 ULP01 A
Bottom left:
(M) TI 1999 [pin 1 marking]