Complete Audio Interface Includes Debounced Pushbutton Interface

Recent media player designs, such as MP3 players, have disconnected the systems’ "brains" (the microcontroller) from the output circuitry. Taking advantage of this change, the MAX5406, a complete audio processor with a simple, debounced pushbutton interface, eliminates the need for an external microprocessor. The device integrates all the op amps and potentiometers needed to implement and control standard audio functions: balance, volume, tone, treble, bass, bass boost, and ambiance. If desired, the Max5406 can still be controlled with a microcontroller.

The processor intelligently controls the wiper advance rate using the company’s proprietary Smart Wiper technology. The wiper advances at a 4-Hz rate after the button has been pushed for 1 s, and at a 16-Hz rate after it has been pushed for 4 s. Integrated bass and treble filter circuitry implements the well-known Baxandall response. The bass and treble corner frequencies are set using small external capacitors. The MAX5406 is primarily targeted at multimedia boom boxes when paired with power amps like the MAX9769. Total harmonic distortion is less than 0.01% and the output noise is less than 25 mV rms. The device operates from a single 2.7-V to 5.25-V supply or a dual plus and minus 2.7-V supply and requires less than 0.5 microamps in shutdown mode. It comes in a 4-by-4-mm TQFN package.