“This is the second Apple-branded chip on the larger iPhone logic board, the other being the processor/ram combination. Various sources around the industry are speculating that Philips/NXP is responsible for the power management chip for the phone. Judging by the Philips copyright symbol, I would have to agree that it is something like an NXP PCF50626 or PCF60633. Some of the chip’s structure can be seen under the metal pattern as well as some exposed circuits. I can see what looks to be three ADCs/comparators on the right side of the chip and at least four charge pumps in the middle and left side (noted by the square capacitors and large drive transistors).
Again, great thanks to Think Secret for sending me the chips!”
Source: http://microblog.routed.net/2007/07/13/ic-friday-iphones-apple-338s0459-mystery-chip/