Headphone Amp Series Grows By Two

Expanding the DirectDrive headphone amplifier series are the MAX9722A and MAX9722B devices with a number unique features. Both employ what is said to be a revolutionary architecture that produces a ground-referenced output from a single supply to eliminate the two dc-blocking capacitors between amplifier and headphone. The devices do not require a dc bias voltage applied to the headphone-jack ground pin, and the differential input structure allows the amplifiers to reject common-mode noise. They can also be configured to sense the headphone return potential, eliminating noise caused by ground loops. Gain for MAX9722B is set internally to -6dB while gain for MAX9722A is set with two external resistors. Other common features include operation from a 2.4V to 5.5V supply, an output power of 60 mW per channel into a 16 ohms load or 130 mW per channel into a 32 ohms load, a 0.02% THD + N, a 90 dB PSRR, and a low-power shutdown mode that reduces consumption to below 100 µA. Prices start at $0.65 each/100,000. MAXIM INTEGRATED PRODUCTS, Sunnyvale, CA. (800) 998-8800.