Headphone Amp

7/21/2003Edited by PETech Staff Maxim Integrated Products’ new MAX4411B headphone amplifier combines the patented stereo DirectDrive technology with a fixed-gain (-2V/V) configuration. This combination eliminates both the bulky dc-blocking capacitors and the external-gain setting resistors. The result is a low-cost, ultracompact headphone amp requiring very few external components and making it ideal for compact, portable equipment with audio playback.

DirectDrive generates a ground-referenced output from a single 1.8V to 3.6V supply, which unlike competing solutions, doesn’t require a mid-rail dc bias voltage to be applied to the headphone jack ground pin. This doubles the dynamic range of the output swing and simplifies end-product design and reliability.

The MAX4411B has a fixed gain of -2V/V, produces 80MW per channel into a 16Ω load, and has very low 0.003% THD + N. A high 86 dB PSRR at 217 Hz allows direct operation from noisy supplies without additional conditioning. Independent left/right, low-power shutdown controls optimize power savings in mixed mode mono/stereo applications. In addition to minimizing size, the elimination of dc-blocking capacitors improves the amplifier's low-frequency response, allowing full-range audio reproduction. This is especially important for music and video playback. Comprehensive click-and-pop reduction circuitry ensures fast turn on/turn off times without audible glitches. The outputs include ±8kV ESD protection.

For more information, visit www.maximic.com