The LM49250 is a fully integrated audio subsystem designed for stereo cell phone applications. The LM49250 combines a 2.4W/Ch stereo class D speaker amplifiers with a 45mW/Ch stereo ground referenced headphone amplifier, a class AB earpiece amplifier, National 3D enhancement, volume control, and an input mixer into a single device. The filterless class D amplifiers deliver 1.2W/Ch into an 8? load with <1% THD+N from a 5V supply.

The LM49250 features a new circuit technology that utilizes a charge pump to generate a negative supply voltage. This allows the headphone outputs to be biased about ground, thereby eliminating the output-coupling capacitors.

For improved noise immunity, the LM49250 features fully differential left, right and mono inputs. The three inputs can be mixed/multiplexed to any output combination of the loudspeaker, headphone or earpiece amplifiers. The left and right differential inputs can be used as separate single-ended inputs, mixing multiple stereo audio sources. The mixer, volume control, and device mode select are controlled through an I 2C compatible interface.

Output short circuit and thermal overload protection prevent the device from being damaged during fault conditions. Superior click and pop suppression eliminates audible transients on power-up/down and during shutdown.