Part Number: TPA6120A2
The 6120A2 dev kit performs very poorly into loads 50 ohms and down, but we have seen products using the chip that perform in a linear fashion up to clipping.
The following is made with an AP 555B and the 6120 dev kit with +/- 7V rails. Two things are clear; it doesn't perform well at 50 ohms or lower, and even at 300 and 600 ohms the distortion is forming a U shaped curve instead of a linear ramp down to a vertical distortion limit.
The dev kit is as bare bones as it comes and doesn't include a schematic (and also has two label errors on the silkscreen which invert input and rail supplies). Increasing the voltage rail made the performance even worse.
We have seen measurements of products using this chip that look like a perfect straight line until clipping for all loads. What can be done to get the 6120 to actually perform to spec and to put out clean low distortion power to clipping below 50 ohms?
