LM4910 is an IC made by National Semiconductors which is intended for low power integrated stereo amplifiers. This amplifier is used to amplify headphones that have low distortion of less than 1%. This amplifier circuit can be operated with a voltage of 3.3VDC with an output of 0.35 Watt at 32 ohms headphone.
This IC has been designed in such a way that it does not need a coupling capacitor on the output line. Capacitors C1 and C2 in the circuit function as decoupling DC inputs on the left and right channels. Whereas R1 and R1 provide obstacles so that the input sensitivity is not too high. Capacitor C3 to help filter the DC voltage from the ripple voltage.
As far as information I can, IC LM4910 is only available in the form of SMD. This circuit can work well at voltages between 2.2V to 5V so that it can be operated with batteries. The headphone load used must have an impedance of 32ohm. Do not use a power supply above 5 volts on this amplifier because it will damage the IC. Amplifiers can be packaged very small without requiring any heatsinks.
Shutdown pin functions to turn off the IC when it will not be used / standby by providing high logic on this pin.