LM4666 - Filterless High Efficiency Stereo 1.2W Switching Audio Amplifier

The LM4666 is a fully integrated single-supply high efficiency switching audio amplifier. It features an innovative modulator that eliminates the LC output filter used with typical switching amplifiers. Eliminating the output filter reduces parts count, simplifies circuit design, and reduces board area. The LM4666 processes analog inputs with a delta-sigma modulation technique that lowers output noise and THD when compared to conventional pulse width modulators.

The LM4666 is designed to meet the demands of mobile phones and other portable communication devices. Operating on a single 3V supply, it is capable of driving 8Ω transducer loads at a continuous average output of 450mW with less than 1%THD+N. Its flexible power supply requirements allow operation from 2.8V to 5.5V.

The LM4666 has high efficiency with an 8Ω transducer load compared to a typical Class AB amplifier. With a 3V supply, the IC's efficiency for a 100mW power level is 79%, reaching 84% at 450mW output power.

The LM4666 features a low-power consumption shutdown mode. Shutdown may be enabled by driving the Shutdown pin to a logic low (GND).

The LM4666 has fixed selectable gain of either 6dB or 12dB. The LM4666 has short circuit protection against a short from the outputs to V_DD or GND.

Products containing the "LM4666" keyword are: LM4666SD , LM4666SD/NOPB , LM4666SD/NOPB , LM4666SD/NOPBNS-SSD , LM4666SDBD , LM4666SDBD , LM4666SDBD/NOPB , LM4666SDBD/NOPB , LM4666SDNOPB , LM4666SDX , LM4666SDX/NOPB , LM4666SDX/NOPB

• No Output Filter Required for Inductive Transducers
• Selectable Gain of 6dB or 12dB
• Very Fast Turn On Time: 6ms (typ)
• Minimum External Components
• "Click and Pop" Suppression Circuitry
• Micro-Power Shutdown Mode
• Short Circuit Protection
• Available in Space-Saving NHK0014A Package

Key Specifications

• Efficiency at 3V, 100mW into 8Ω Transducer: 79% (typ)
• Efficiency at 3V, 450mW into 8Ω Transducer: 84% (typ)
• Efficiency at 5V, 1W into 8Ω Transducer: 85% (typ)
• Total Quiescent Power Supply Current: 7.0mA (typ)
• Total Shutdown Power Supply Current: 0.02µA (typ)
• Single supply range: 2.8V to 5.5V

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