Headphone amp with DirectDrive — what the 60 mW rating means on the bench
The MAX9728AETC+ is a Class AB stereo headphone amplifier from Analog Devices' DirectDrive series, delivering 60 mW per channel into a 32 Ω load. That output level is enough to drive most consumer and pro-audio headphones to comfortable listening levels without the pop or thump you get from a single-supply amp that needs a DC-blocking cap — the DirectDrive architecture generates a regulated negative rail internally, so the output sits at 0 VDC and the headphones couple directly.
Package, footprint, and what the TQFN tells you about rework
If you are replacing a failed part on a board, check that the pad layout matches — the centre pad is the thermal and ground connection, and a missing via under it traps heat.
Protection features and the DirectDrive advantage
On-chip short-circuit and thermal protection mean the output stage shuts down before a fault cooks the die — useful when a headphone jack gets yanked or a solder bridge shorts the output to ground during assembly. The shutdown pin lets a microcontroller or a power-management sequencer put the amp into a low-power state when the audio path is idle. The DirectDrive series eliminates the need for large DC-blocking capacitors on the output, which saves board area and removes the low-frequency roll-off those caps introduce. For a portable design where every mm² counts, that is a real advantage over a conventional single-supply headphone amp.