LM4910 minimum output noise reduce the output power circuit

The circuit for the LM4910 is designed to minimize output noise and reduce power consumption. The output noise is attenuated by utilizing a resistor in series with the load. A feedback resistor Rf is used in conjunction with a frequency bypass capacitor Cf to suppress high-frequency noise. A short jumper J1 is included; when J1 is grounded, the amplifier enters shutdown mode, minimizing power consumption. When J1 is open (VDD high), the amplifier operates normally, with maximum power determined by the equation PDMAX = 4VDD²/2RL.

The LM4910 circuit configuration aims to enhance audio performance by minimizing noise and optimizing power efficiency. The series resistor connected to the output terminal serves as a low-pass filter, effectively reducing the amplitude of unwanted noise signals that may interfere with the desired audio output. The choice of resistance value is critical, as it directly influences the attenuation level of the output noise.

The feedback resistor Rf is paired with a bypass capacitor Cf to form a high-frequency noise suppression network. This configuration allows for the filtering of high-frequency components that could degrade audio quality. The capacitor Cf should be selected based on the desired cutoff frequency, ensuring effective suppression of noise while maintaining the integrity of the audio signal.

The inclusion of jumper J1 provides flexibility in power management. In shutdown mode, the amplifier's power consumption is significantly reduced, which is beneficial in battery-operated devices where energy efficiency is paramount. The transition from shutdown to active mode is controlled by the state of jumper J1; when connected to ground, the amplifier is disabled, and when left open, it operates at full capacity. The maximum power output of the amplifier is calculated using the formula PDMAX = 4VDD²/2RL, where VDD is the supply voltage and RL is the load resistance. This relationship highlights the importance of selecting appropriate values for both VDD and RL to achieve optimal performance from the LM4910 amplifier. As shown for the LM4910 minimum output noise/reduce the output power circuit. Reduce output noise measures are: between the output terminal of a resistor in series with the loa d Rseries, so that the output noise can be attenuated, to achieve the purpose of reducing noise; in parallel across the feedback resistor Rf frequency bypass capacitor Cf, with to suppress high frequency noise. J1 short jumper, when short jumper J1 is grounded, the amplifier is in shutdown mode, the power consumption to a minimum; when J1 short jumper off (VDD high), the amplifier is in working mode, the power PDMAX 4VDD2/2RL.