1.25-W, mono Class-D audio amplifier with integrated 125-mW earpiece amp & 42-mW headphone amp

The LM49151 is a fully integrated audio subsystem designed for portable handheld applications such as cellular phones. The LM49151 combines a 1.25W mono E2S class D amplifier, 125mW Class AB earpiece driver, 42mW/channel stereo ground referenced headphone drivers, volume control, input mixer/multiplexer, and speaker protection into a single device.

The LM49151 class D speaker amplifier features Texas Instruments' unique Automatic Level Control (ALC) that provides both a I2C programmable no-clip feature with Clip Controls and speaker protection. The E2S (Enhanced Emission Suppression) class D amplifier features a patented, ultra low EMI PWM architecture that significantly reduces RF emissions while preserving audio quality and efficiency while delivering 1.25W into an 8Ω load with <1% THD+N with a 5V supply. The 42mW/channel headphone drivers feature Texas Instruments' 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.

The LM49151 features separate volume controls for the loudspeaker and headphone inputs. Mode selection, shutdown control, and volume are controlled through an I2C compatible interface. The LM49151's superior click and pop suppression eliminates audible transients on power-up/down and during shutdown.