Hello all!

I'm trying to design a HiFi audio player around an ES9039Q2M and have come with some designs to adapt the output of the DAC in order to drive headphones with a decent amount of power available.

My main goals to achieve are lower than -100dB THD+N and more than 40mW output power at 600ohms. To do so, I've chosen to go for a fully balanced topology and have dual rails for power delivery at +5V and -5V.

The designs I've come up with are mainly based on the ones provided in the ES9039Q2M datasheet itself and in the TIPD177 reference design from Texas Instruments.

The first schematic is similar to the one in the TI reference design TIPD177 but instead of having a single opamp at the power stage, making it single-ended, it has one opamp for each of the outputs of the previous I/V stage in order to provide a balanced output.

The second one consists of the reference design found on the ES9039Q2M datasheet with a couple of OPA1622 set as buffers for each of the outputs of the previous stage, so that they can deliver enough output current.

The last one also has the same I/V stage found in the ES9039Q2M datasheet but each of its OPA1622 from the power stage have their inputs connected to the positive and negative outputs of the I/V stage.

I've simulated the three circuits in PSPice and KiCAD and the three of them look good, but I wanted to know if I'm missing anything or the designs have any major problems. This is my first design of this kind and I haven't been able to find any clear examples online.

I know many products currently use some kind of topology similar to this, either using OPA1612/22, SGM8262 or AD8397. I was hoping if you could share your opinions or your experience in this area.

Thanks!

Headphone and I/V stage for DAC