Auto Headphone Amps Integrate Protection Circuitry

The MAX13330 and MAX13331 stereo headphone amplifiers target automotive entertainment systems in which board space is at a premium and high-voltage protection is critical. Built-in circuitry protects outputs against shorts to battery/ground and load dumps up to 45 V, reducing space requirements and cost by eliminating discrete components. They also integrate a short-circuit diagnostic output to simplify fault analysis and ±15-kV ESD protection (human body model). Gain is set internally to -1.5 V/V for the MAX13330 and adjusted externally for the MAX13331. Both devices operate from a single 4- to 5.5-V supply, feature 0.009% THD+N, and can deliver up to 75 mW per channel into an 8-ohm load, 100 mW into a 16-ohm load, or 130 mW into a 32-ohm load. A power-supply rejection ratio of 80 dB at 217 Hz allows the amplifiers to operate from noisy digital supplies without an additional linear regulator or filtering. Comprehensive click-and-pop circuitry suppresses audible clicks and pops on startup and shutdown, ensuring fast turn-on/turn-off times without audible glitches. A low-power shutdown mode reduces the supply current to less than 2 µA. Fully specified over the -40°C to 105°C AEC-Q100 Level 2 automotive temperature range, the MAX13330/MAX13331 are available in a 4- by 5-mm, 16-pin QSOP package. Prices start at $1.00 for 1000. MAXIM INTEGRATED PRODUCTS, Sunnyvale, CA. (800) 998-8800.