I am trying to build a circuit using Yamaha Sound chip YM2151 with Yamaha DAC YM3012. This is my first attempt in doing anything with analog signals, so there is much to learn!
While reading a datasheet, I stumbled across the below schematic which shows Analog Ground.
Can someone please explain how it works? Why is there 10/15 V if my circuit required 5 V? How do I build this part of the circuit?
Best Answer
I only found the 1992 data sheet so maybe yours is later but it did contain a schematic that helps.
I've superimposed your circuit (lower down) with an extract from the data sheet (higher up) and, on your circuit, I've corrected what appears to be a mistake (shown by the red dot): -
It's actually +/- 12 volts to put a number on it. You need to use an external dual supply for the op-amp circuits.
Get hold of a DC-to-DC converter from the likes of TRACO (for instance) - they produce dual output types and 12 volts (as well as 10 volts and 15 volts) are standard parts. The input supply for the TRACO would nominally be 5 volts and attached to your 5 volt and digital ground.
Analogue ground is connected to digital ground at just one point (the red circled point that seems to be omitted in your diagram). Any digital circuits in excess of the Yamaha chip will tee-off from that point - this prevents noisy digital currents influencing nice clean analogue currents on the analogue ground.