A Two-Step Time-to-Digital Converter using Ring Oscillator Time Amplifier

A two-step time-to-digital converter using a ring oscillator time amplifier is presented. The time amplifier structure does not accumulates the error in the iterative process of time. There are 8 bits in total, of which 4 bits are obtained in the coarse conversion and 4 bits are obtained in the fine conversion by amplifying the remaining time. The TDC circuit occupied an area of 0.34 mm² using 180 nm CMOS process. The effective number of bits is 7.42bits. The TDC circuit has shown 10.5 ps resolution for a 50 MHz. The DNL and INL are 0.7(LSB) and 0.5(LSB), respectively. The power consumption is 1.34 mW with a 1.8 V supply.