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1.2.2.3 Audio Amplifier: NS LM4867
General Description
The LM4867 is a dual bridge-connected audio power amplifier which, when connected to a 5V supply, will
deliver 2.1W to a 4Ω load or 2.4W to a 3Ω load with less than 1.0% THD+N. The LM4867 uses advanced, latest
generation circuitry to eliminate all traces of clicks and pops when the supply voltage is first applied. The
amplifier has a headphone-amplifier-select input pin. It is used to switch the amplifiers from bridge to
single-ended mode for driving headphones. A new circuit topology eliminates headphone output coupling
capacitors. A MUX control pin allows selection between the two sets of stereo input signals. The MUX
control can also be used to select between two different customer-specified closed-loop responses.
Boomer audio power amplifiers are designed specifically to provide high quality output power from a surface
mount package and require few external components. To simplify audio system design, the LM4867 combines
dual bridge speaker amplifiers and stereo headphone amplifiers in one package.
The LM4867 features an externally controlled power-saving micropower shutdown mode, a stereo
headphone amplifier mode, and thermal shutdown protection.
Features
Advanced "click and pop" suppression circuitry
Eliminates headphone amplifier output coupling capacitors
Stereo headphone amplifier mode
Input mux control and two separate inputs per channel
Thermal shutdown protection circuitry
LLP, TSSOP, and exposed-DAP TSSOP packaging available
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