Time precision comparison of digitally controlled delay elements

This paper compares the time precision of different digitally controlled delay cells. Other design metrics as delay, signal integrity, power and area are also considered. The precision is evaluated by the cell´s uncertainty, given as the ratio between jitter and time delay, considering both thermal and power supply noise. The comparison is based on circuit simulation, in a 180 nm technology, using the SPECTRE tool from Cadence. The comparison results will help the designer to choose the most appropriate delay cell for low uncertainty design.