Specifications
- Input : I2S, bitdepth from 16 to 32 bits, sampling rate upto 768khz,
- Asynchronous FIFO built-in,
- FPGA-based delta-sigma digital to analog converter (DAC),
- 256-step digital volume,
- Full balanced outputs,
- Compatible with Raspberry Pi 3/3B+/4 connection,
- Ultra-low phase noise oscillators with high precision linear low drop voltage regulators are designed specifically for High-Definition audio (HD audio).
Schematic and PCB design
Schematic and PCB were designed using Free open software KiCad
https://www.kicad.org/
Power supply for FPGA Cyclone IV
Oscillator block with 2 separated oscillators. Each one will provide clock for each sampling rate family (44.1 or 48)
3rd order Low pass filter
PCB layout with 4 layers
FPGA programming
(to be continued…)