The packaging is actually pretty unusual. It is a wafer level chip-scale bare die assembly, where the die has an RDL (metal redistribution layer) and solder balls directly flip chipped to the board. The die marking is a laser marking on the back of the silicon die. Here is the die “undressed.” . It’s a small, 1.35 mm x 0.85 mm, die made by Texas Instruments with die markings of CDPS3271C.

The die markings clarify the part number, which is actually a typical TI date code. The 8x represents the year and month, and the next four characters are the lot code. Therefore, our three parts were made in September ’08 (89), October ’08 (8A), and December ’08 (8C). Taking a peek at it down the microscope, it looks like it is fabricated with a three metal BiCMOS process, likely 0.25 µm or 0.18 µm. There is not really a lot of circuitry on the die, but then again how much is really needed to relay the button commands to the processor chip – just the volume controller and the interface for the capacitative sensors on the back of the board.

So no DRM, no microphone; just a high volume design win for Texas Instruments.