The background
Click on the picture to see a larger view of the pcb.
This headphone amplifier is based on the extremely high performing TPA6120. I saw this IC some time ago and I was very astonished by the extremely low distortion figures 0.000021% and the extreme speed, 100 MHz. Observe the zeros in the distortion figures! I don't think I have seen anything lower. Remember though that distortion figures aren't everything but high speed is always good and certainly in combination with low distortion. Based on these facts I have decided to let this headphone amp IC have a go.
This project is not suitable for a newbeginner, but if you only have a soldering iron with a very fine tip and you don't tremble and have a good pair of tweezers, it shouldn't be any problems to succeed. This amp is not very hard to solder, yes I'm not kidding and it's really cool, not common DIY stuff!
Notice that TPA6120 has a very special package which may be a bit hard to solder. See my instructions about this.
The package is called PowerPAD and more info about this is found here.
Quote from Texas Instruments:
The PowerPAD thermally enhanced package provides greater design flexibility and increased thermal efficiency in a standard size IC package. PowerPAD's improved performance permits higher clock speeds, more compact systems and more aggressive design criteria.
PowerPAD packages are available in several standard surface mount configurations. They can be mounted using standard printed circuit board (PCB) assembly techniques, and can be removed and replaced using standard repair procedures.
To make optimum use of the thermal efficiencies designed into the PowerPAD package, the PCB must be designed with this technology in mind. This document will focus on the specifics of integrating a PowerPAD package into the PCB design.
This is what Texas Instruments wants to say about their new ultra extreme headphone amp IC.
The TPA6120A2 is a high fidelity audio amplifier built on a current-feedback architecture. This high bandwidth, extremely low noise device is ideal for high performance equipment. The better than 120 dB of dynamic range exceeds the capabilities of the human ear, ensuring that nothing audible is lost due to the amplifier. The solid design and performance of the TPA6120A2 ensures that music, not the amplifier, is heard.
Evaluation module
Texas Instruments has made an evaluation module which can be bought for a rather cheap price. This module has a good documentation which can be found here.
Active elements are AD8610 OPA134 or OPA627 and a headphone amp TPA6120. The operational amplifiers are one of the best in their market segments. The AD8610 is new and very interesting and I have chosen this to be my reference opamp. Any high performing opamp
