Low-power mobile sound system has noise suppression

The device combines a noise suppression microphone amplifier, a 1.35-W mono class-D amplifier with ALC, a class-AB earpiece driver with AGC, a high-efficiency, stereo, ground-referenced headphone amplifier with click/pop suppression and I2C mode select and volume control. Quiescent current consumption is 3.7 mA for the earpiece amplifier and microphone amplifier signal path.

The LM49155's uplink noise suppression technology rejects far-field noise at 34 dB at 1kHz through a two-microphone amplifier implementation. Downlink voice intelligibility is improved by enhancing the SNR (by 16 dB typ) between the handset's earpiece signal level and the ambient noise level.

The LM49155 is packaged in a 36-bump micro SMD package measuring 3.4mm x 3.4mm. Pricing is $2.25 each in 1,000-unit quantities.

- Rich Pell
EE Times