A 3.6mW, 90nm CMOS Gated-Vernier Time-to-Digital Converter with an Equivalent Resolution of 3.2ps

Two gated ring oscillators (GROs) act as the delay lines in an improved Vernier time-to-digital converter (TDC), where the already small quantization noise of the standard Vernier TDC is further first-order shaped by the GRO operation. The TDC has been implemented in a 90nm CMOS process and consumes 3mA from 1.2V when operating at 25MHz. The native Vernier resolution of the TDC is 5.8ps, while the total noise integrated over a bandwidth of 800kHz yields an equivalent TDC resolution of 3.2ps