LM4674A - Filterless 2.5 Stereo Class D Audio Power Amplifier

The LM4674A is a single supply, high efficiency, 2.5W/channel, filterless switching audio amplifier. A low noise PWM architecture eliminates the output filter, reducing external component count, board area consumption, system cost, and simplifying design.

The LM4674A is designed to meet the demands of mobile phones and other portable communication devices. Operating from a single 5V supply, the device is capable of delivering 2.5W/channel of continuous output power to a 4Ω load with less than 10% THD+N. Flexible power supply requirements allow operation from 2.4V to 5.5V.

The LM4674A features high efficiency compared to conventional Class AB amplifiers. When driving an 8Ω speaker from a 3.6V supply, the device features 85% efficiency at P_O = 500mW. Four gain options are pin selectable through the GAIN0 and GAIN1 pins.

Output short circuit protection prevents the device from being damaged during fault conditions. Superior click and pop suppression eliminates audible transients on power-up/down and during shutdown. Independent left/right shutdown controls maximizes power savings in mixed mono/stereo applications.

Products containing the "LM4674A" keyword are: LM4674ATL , LM4674ATL/NOPB , LM4674ATL/NOPB , LM4674ATLBD , LM4674ATLBD/NOPB , LM4674ATLX , LM4674ATLX , AP3605FNTR- , LM4674ATLX GI2 , LM4674ATLX NOPB , LM4674ATLX+ , LM4674ATLX/NOPB , LM4674ATLX/NOPB , LM4674ATLXNOPB

• Output Short Circuit Protection
• Stereo Class D Operation
• No Output Filter Required
• Logic Selectable Gain
• Independent Shutdown Control
• Minimum External Components
• Click and Pop Suppression
• Micro-Power Shutdown
• Available in Space-Saving 2mm x 2mm x 0.6mm DSBGA Package

Key Specifications

• Efficiency at 3.6V, 100mW into 8Ω 80% (typ)
• Efficiency at 3.6V, 500mW into 8Ω 85% (typ)
• Efficiency at 5V, 1W into 8Ω 85% (typ)
• Quiescent Power Supply Current at 3.6V Supply 4mA
• Power Output at V_DD = 5V, R_L = 4Ω, THD ≤ 10% 2.5W (typ)
• Power Output at V_DD = 5V, R_L = 8Ω, THD ≤ 10% 1.5W (typ)
• Shutdown Current 0.1μA (typ)

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