The LME49600 is a high performance, low distortion high fidelity 250mA audio buffer. Whereas there are many uses for the LME49600, this application report describes a headphone amplifier circuit and associated demonstration board. Designed for use inside an operational amplifier’s feedback loop, it increases output current, improves capacitive load drive, and eliminates thermal feedback.
The LME49600 offers a pin-selectable bandwidth: a low current, 110MHz bandwidth mode that consumes
8mA and a wide 180 MHz bandwidth mode that consumes 15mA. In both modes the LME49600 has a nominal 2000V/μs slew rate. Bandwidth is easily adjusted by either leaving the BW pin unconnected, connecting a resistor between the BW pin and the VEE pin or connecting the BW pin directly to the VEE pin.
The LME49600 is fully protected through internal current limit and thermal shutdown.
To help the user investigate and evaluate the LME49600's performance and capabilities, a fully populated demonstration board was created. Please contact the Audio Products Group for availability. This board is shown in Figure 1. Connected to an external power supply (±2.5V to ±17V) and a signal source. The LME49600 demonstration board easily demonstrates the amplifier's features.