This my fist project with SMD circuit. I ignored SMD because the small sized parts are confused me. The circuit of current SMD project is the headphone amplifier with TPA6120.
Step 1: Design Schematic and Footprint
I designed three PCB of this really simple schematic for prototypes only. Finlay I will use this headphone amp within my bigger project of modular audio mixer. The official schematic is really simple, but unbalanced/balanced converter required. I did not found footprint for this project, I have to create it with Altium Designer. This part have 20 pins, bit the 21st pin is on the bottom of circuit, which is the heatsink and the GND.
Step 2: Design Variations of PCB for Prototypes
I designer 3 versions of PCBs to see the differences between the features of TPA6120. The output jack and volume potentiometer included to the first and second versions only. These boards are bigger than the 3rd, but in the last version I have input headers for balanced sources and separated power supplies to measure the benefits of these features. This is the reason why the volume pot missing from this board. I wonder, how better with balanced input and with separated power supply. My blogpost about this idea: