Features • Output Short Circuit Protection • Thermal Overload Protection • Stereo filterless Class D operation • Spread spectrum modulation • Ground referenced Headphone Drivers • I 2C Control Interface • 32-step input volume control • Output volume control • Minimum external components • Click and Pop suppression • Micro-power shutdown • Available in space-saving 36–bump µSMD package • Single supply operation • RF suppression Description 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 8Ω 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. Key Specification ■  Power Output at VDD = 5V    Speaker:   RL = 4Ω, THD+N ≤ 1%   RL = 4Ω, THD+N ≤ 10%   RL = 8Ω, THD+N ≤ 1% 1.97W/Ch 2.4W/Ch 1.2W/Ch  Headphone:   RL = 16Ω, THD+N ≤ 1%   RL = 32Ω, THD+N ≤ 1% 41mW/Ch 45mW/Ch  Earpiece:   RL = 16Ω, THD+N ≤ 1%   RL = 32Ω, THD+N ≤ 1% 170mW 90mW ■  Shutdown Current 0.1μA ■  Efficiency at 5V, 1W into 8Ω 87% ■  Efficiency at 3.6V, 500mW into 8Ω 85% Applications • Mobile phones • Portable Navigation Devices • Portable Media Players

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Datasheet

Title		Size	Date	Other Language
	LM49250  Enhanced Emissions Suppression Stereo Class D Audio Sub-System with Ground Referenced Headphone Amplifier and Mono Earpiece	1350 Kbytes	15-Dec-08

Featured Application Notes

Title		Size	Date	Other Language
	AN-1964: Application Note 1964 LM49151 Demonstration Board and Software Guide	1605 Kbytes	13-May-09	中文

More Application Notes

Title		Size	Date	Other Language
	AN-1964: Application Note 1964 LM49151 Demonstration Board and Software Guide	1605 Kbytes	13-May-09	中文