MAX9770

19-3134; Rev 0; 5/04 1.2W Low-EMI, Filterless, Mono Class D Amplifier with Stereo DirectDrive Headphone Amplifiers General Description The MAX9770 combines a mono, filterless, Class D speaker amplifier and stereo DirectDrive headphone amplifiers in a single device. The MAX9770 operates from a single 2.5V to 5.5V supply and includes features that reduce external component count, system cost, board space, and offer improved audio reproduction. The speaker amplifier makes use of Maxim’s patented Class D architecture, providing Class AB performance with Class D efficiency, conserving board space, and extending battery life. The speaker amplifier delivers 1.2W into an 8Ω load while offering efficiencies above 85%. A spread-spectrum scheme reduces radiated emissions caused by the modulation frequency. Furthermore, the MAX9770 oscillator can be synchronized to an external clock through the SYNC input, avoiding possible problem frequencies inside a system. The speaker amplifier features a low 0.025% THD+N, high 70dB PSRR, and SNR in excess of 90dB. The headphone amplifiers feature Maxim’s patented DirectDrive architecture that produces a ground-referenced output from a single supply, eliminating the need for large DC-blocking capacitors. The headphone amplifiers deliver up to 80mW into a 16Ω load, feature low 0.015% THD+N, high 80dB PSRR, and ±8kV ESD-protected outputs. A headphone sense input detects the presence of a headphone, and automatically configures the amplifiers for eithe...