DirectDrive Headphone Amplifiers: A Maxim First!
The DirectDrive difference: conventional headphone amplifiers bias the output signal at VCC/2. DirectDrive generates an internal -VCC from the positive supply. This allows the audio output signal to be biased at 0V DC, eliminating bulky DC-blocking capacitors!
DirectDrive Advantages
- Saves the cost and space of DC-blocking caps.
Especially critical in compact equipment such as cell phones, PDAs, and notebook computers.
- Produces industry-leading click/pop performance levels.
The DC output level remains at 0V on power and shutdown cycles. To learn more about quantitative measurement of click-and-pop noise, read the EDN article "Quantitative Analysis Yields Objective Audio-Amplifier Click and Pop Measurements".
- Produces 4x more output power from a single 3.3V supply.
DirectDrive produces an output signal that is twice the amplitude of conventional amplifiers. This makes it possible to drive a 2VRMS line-level signal from a single 3.3V supply. See Application Note 3354 to learn more.
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