MAX9721CETC+

Audio Amplifiers Overview

The MAX9721CETC+ is a fixed-gain, stereo headphone amplifier utilizing DirectDrive architecture to produce ground-referenced outputs from a single supply. It operates on a 0.9V to 1.8V voltage range with a typical quiescent current of 2.2mA and shutdown current of 1.0µA. The device delivers up to 20mW per channel into a 32Ω load with 0.006% THD+N. It features an internal gain of -1V/V, 80dB PSRR at 1kHz, ±8kV ESD protection, and integrated click-and-pop suppression. The component is housed in a 12-pin thin QFN package (4mm x 4mm x 0.8mm) and functions within a temperature range of -40°C to +85°C.

Audio Amplifiers Feature Summary

• DirectDrive technology eliminates the need for large DC-blocking output capacitors by generating an internal negative supply rail via a charge pump.
• Fixed gain configuration removes the requirement for external feedback networks, reducing system component count.
• Integrated comprehensive click-and-pop circuitry suppresses audible transients during power-up and shutdown sequences.
• Low-power shutdown mode significantly reduces supply current consumption when the amplifier is disabled.

Audio Amplifiers Applications

• MP3 Players
• Cellular Phones
• PDAs
• Smart Phones
• Portable Audio Equipment

Audio Amplifiers Procurement Notes

Verify the specific suffix ET indicates the 12-pin Thin QFN package variant rather than the UCSP option. Confirm the C designation corresponds to the -1V/V fixed gain setting required for the design. Ensure the ordering code matches the exact manufacturer part number to avoid pinout or performance discrepancies.

Audio Amplifiers Selection Notes

Select this model for applications requiring minimal board space due to the elimination of bulky output coupling capacitors. The low supply voltage operation allows direct powering from single-cell batteries. Verify that the -1V/V gain aligns with the source signal amplitude requirements before implementation.

Audio Amplifiers Part Context

This component belongs to the MAX9721 family of stereo headphone amplifiers designed for portable electronics. The series includes variants with different fixed gains (-2V/V, -1.5V/V, and -1V/V) and packaging options. The DirectDrive architecture distinguishes these devices from conventional single-supply drivers by providing ground-referenced outputs.

Audio Amplifiers Replacement Considerations

MAX9721AEBC-T

Audio Amplifiers FAQ

How does the DirectDrive architecture affect low-frequency response?

By eliminating large DC-blocking capacitors, the DirectDrive architecture prevents the high-pass filtering effect that typically attenuates low frequencies and introduces distortion in conventional headphone drivers.

What is the function of the PVSS pin?

The PVSS pin provides the inverted negative supply voltage generated by the internal charge pump, which biases the amplifier outputs about ground to increase dynamic range.