iPhone 4 audio codec chip
http://www.ifixit.com/Teardown/iPhone-4-Teardown/3130/3
Cirrus Logic 338S0589 audio codec (Apple branded). This is the same part as in the iPad.

iPhone 4s audio codec chip
http://www.ifixit.com/Teardown/iPhone-4S-Teardown/6610/2*Step 10
Apple 338S0987 B0FL1129 SGP, believed by Chipworks to be a Cirrus Logic audio codec chip

Older gen
http://www.ifixit.com/Browse/iPhone

iPod Touch 4 audio codec chip
http://www.ifixit.com/Teardown/iPod-Touch-...Teardown/3562/3*Step 21
On the far left is a 338S0859 chip. It's similar to the Cirrus Logic audio codec of the iPhone 4 (338S0589).

Older gen and other model
http://www.ifixit.com/Browse/iPod

iPad
http://www.ifixit.com/Browse/iPad

This post has been edited by wkkm007: Nov 15 2011, 02:33 PM

Good question I also would like to ask
Anyone have iPhone 4s?
Let see Apple whether they upgrade the chip?

This post has been edited by wkkm007: Nov 12 2011, 11:40 AM

This mean I make a right choice to IPT4