fyi, just found a comparison chart of USB PHY:
http://www.ebv.com/fileadmin/product...sceivers_1.pdf

and checked out the isp1704a because of its similarity to the 1707:
http://www.stericsson.com/product/222222.jsp

It is 100% pin-compatible to the chip in the N900-schematic (which only misses ID and PSW, in comparison to isp1704a, but ID should be present somehow, considering its an OTG chip…)

happy reading