Time-To-Digital Converter with adjustable resolution using a digital Vernier Ring Oscillator

In this paper, we present the development of a high resolution, and low power, Time to Digital Converter (TDC) based on Vernier Ring Oscillators (VRO) made of standard XOR delay cells. The TDC is aimed at exploiting the excellent timing performance of the Resistive Plate Chambers detector (RPC). The frequency of each Ring Oscillator (RO) is adjustable thanks to a 9-bit serial register from 340 MHz to 370 MHz, allowing, theoretically an LSB selection down to one 1 ps. The core area measures 35µm× 75µm in a 130 nm CMOS technology. Under 1.2 V, the TDC consumes 2.3 mA RMS and 260 nA RMS with or without signal respectively.