A 0.7mW 13b temperature-stable MASH ΔΣ TDC with delay-line assisted calibration

A 1-1-1 MASH AX Time-to-Digital Converter (TDC) with 6ps time resolution is implemented in 0.13μm CMOS. It achieves an ENOB of 13b and a wide input range of 100ns. The TDC exhibits stability within a temperature range of -20 to 120°C, which credits to the use of an on-chip bandgap reference and passive RC oscillators. A novel delay-line assisted online calibration technique is introduced to mitigate the skew error caused by the large comparator delay. The chip consumes only 0.7mW from 1.2V supply, and occupies 0.08mm² area (core).