Description
The LM49270 is a fully integrated audio subsystem designed for stereo multimedia applications. The LM49270 combines a 2.2Wstereo Class D amplifier with a 155mW stereo headphone amplifier, volume control, headphone sense, and National’s unique 3Dsound enhancement into a single device. The LM49270 uses flexible I2C control interface for multiple application requirements. The filterless stereo class D amplifiers delivers 2.2W/channel into a 4? load with less than 10% THD+N with a 5V supply. Theheadphone amplifier features National’s Output Capacitor-less (OCL) architecture that eliminates the output coupling capacitorsrequired by traditional headphone amplifiers. The IC features a headphone sense input (HPS) that automatically detects the presence of a headphone and configures the deviceaccordingly. The LM49270 can automatically switch from OCL headphone output to a line driver output. If the VOC pin is pulledto GND, the VOC amplifier is disabled and the VOC pin is internally set to GND. This feature allows the LM49270 to be usedas a line driver in OCL mode without a GND conflict on the headphone jack sleeve. Additionally, the headphone amplifier canbe configured as capacitively coupled (CC). The LM49270 features a 32 step volume control for the headphone and stereo outputs. The device mode select and volume arecontrolled through an I2C compatible interface. Output short circuit and thermal shutdown protection prevent the device from being damaged during fault conditions.Superiorclick and pop suppression eliminates audible transients on power-up/down and during shutdown. The LM49270 is available ina space saving 28-pin, 5x5mm LLP package.
Selectable OCL/CC headphone amplifier Headphone sense ability National’s 3D Enhancement RF suppression I
