DirectDrive headphone amplifier for low-voltage portable audio
The MAX9721CETC is a Class AB stereo headphone amplifier from Analog Devices' DirectDrive® series, delivering 25 mW per channel into a 16 Ω load. The DirectDrive architecture generates a regulated negative supply internally, eliminating the need for large DC-blocking output capacitors — a key advantage for space-constrained portable designs where the PCB area and BOM height matter. It operates from a 0.9 V to 1.8 V supply rail, suiting single-cell alkaline or Li-ion battery applications where the rail drops below 1.8 V as the cell discharges. The wide supply range means the amplifier continues delivering rated output down to the battery's end-of-life voltage, not just at the fresh-cell level. The part is rated for -40°C to +85°C ambient, covering the industrial temperature band — it can live in outdoor handhelds, automotive cabin electronics, or factory-floor audio interfaces without derating.
Package and footprint for board integration
Housed in a 12-WQFN with exposed pad (4x4 mm body, 12-TQFN supplier package), the MAX9721CETC requires a thermal land pattern on the PCB to sink heat from the output stage. The exposed pad must be soldered to a copper plane — floating it raises the junction temperature above the datasheet limit at full output into 16 Ω. Surface-mount assembly with a 0.50 mm pitch QFN footprint; the centre pad is the primary thermal and electrical ground connection. Stencil aperture should cover 50-70% of the pad area to avoid solder voiding under the die attach.
Sourcing and compliance reality
The part is quoted to order against the BOM quantity; availability and current pricing are confirmed at RFQ time through independent distribution channels. RoHS non-compliant. For designs requiring RoHS exemption or lead-free assembly, verify the solder alloy compatibility and confirm whether a RoHS-compliant variant (MAX9721CETC+) exists for your BOM revision.