The DAC IC function is to convert digital data into analogue. To perform this function the DAC needs to do two main tasks:
- convert the digital number in an analogue voltage or current with the best precision related to the number of bits available
- place this analogue value with the best precision in the time axis
The first task depends mainly on the DAC IC itself, the second from the precision of the time reference (master clock). In the next figure we can see what happens if the clock edge is not always placed in the exact same position; there is an uncertainty on the position of the clock edge called jitter.
It is easy to understand that the clock precision is one of the most important parameters in the analogue signal reconstruction. So in our DAC units we use high precision and stable clock reference. But the precision of the clock itself is not sufficient to ensure the expected precision; the clock distribution paths from the source to the ICs that use the clock is critical and need to be carefully designed.