LM4809

The LM4809 is a Class AB, dual-channel audio power amplifier. It delivers 105mW average output power per channel (5V supply, 16Ω load, THD+N=0.1%), with total harmonic distortion plus noise less than 0.1% across the audio frequency range (20Hz~20KHz). The LM4809 features a simple application circuit requiring minimal external components. No bootstrap capacitors or snubber networks are needed at the output. Available in MSOP and SOP packages, it minimizes board area and is ideally suited for mobile phones and other portable devices requiring low-voltage, low-power solutions. The LM4809 supports shutdown mode via an external control signal to reduce power consumption, and incorporates an internal thermal shutdown protection mechanism. The LM4809 operates with high stability, featuring a gain-bandwidth product of up to 2.5MHz with unity-gain stability. External feedback resistors allow flexible gain configuration for ease of use.

Applications

• Headphone amplifier
• Personal mobile terminal (PDA)
• Karaoke microphone
• Microphone preamplifier

Key features

• High Power Supply Rejection Ratio (PSRR): 70dB at 217Hz and 1KHz
• THD+N <0.1% at 105mW output power into 16Ω load (f=1KHz)
• THD+N <0.1% at 170mW output power into 32Ω load (f=1KHz)
• Low shutdown leakage current, typical 0.4μA
• Compact MSOP and SOP packages for reduced board space
• Excellent pop-and-click suppression during power-up and power-down
• Wide supply voltage range: 2.0V–6V
• No bootstrap capacitor required
• Unity-gain stable