On Tue, Mar 9, 2010 at 5:41 PM, Xiaofan Chen wrote: > I assume you will not have galvanic isolation. I'm pretty sure that the idea is DOA without isolation. Analog Devices makes chips suited for this purpose: http://www.ubasics.com/usb_isolator Both chips would fit on a double sided PCB in a 10x10mm area, with a little more space for the passives, and in 1k quantities are around $10 - which is reasonable. Could be overmolded in the USB A connector. -Adam -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist