LM49450

The LM49450 is a fully integrated audio subsystem designed for portable media player applications. The LM49450 combines a 24-bit I²S digital-to-analog converter (DAC), 2.5W/channel stereo Class D speaker drivers, 36mW stereo ground referenced headphone drivers, volume control, and TI’s unique 3D sound enhancement into a single device.

The filterless Class D amplifiers deliver 1.25W/channel into an 8Ω load with <1% THD+N with a 5V supply. The LM49450 offers two logic selectable modulation schemes, fixed frequency mode, and an EMI reducing spread spectrum mode. The 36mW/channel headphone drivers feature TI’s ground referenced architecture that creates a ground-referenced output from a single supply, eliminating the need for bulky and expensive DC-blocking capacitors, saving space and minimizing system cost. A headphone sense input (HPS) automatically detects the presence of a headphone, and configures the device accordingly.

The LM49450 stereo, 24-bit DAC supports a wide range of sample rates (including 192kHz, 96kHz, 48kHz, and 44.1kHz). The digital audio signal path features better than 100dB SNR, and low 0.05% THD+N when measured at the headphone outputs. The flexible 3-wire I²S interface supports left or right justified audio data.

The LM49450 features separate 32-step volume control for the headphones and speaker outputs. 3D enhancement, mode selection, shutdown control, and volume are controlled through an I²C 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. The LM49450 is available in a space saving 32-pin WQFN package.