In this paper, a highly linear voltage to time converter is presented. It can be used as a brick in the architecture of time-domain analog-to-digital converter. It is based on injection locked oscillators as phase shifter. The injection locked oscillator is implemented using a relaxation oscillator that has been chosen for its high linearity compared to other conventional architectures. The analog-to-time domain converter is designed using 0.18μm Partially Depleted Silicon On Insulator technology. It converts the analog information into time-domain information as a phase shift and it has a linearity range of 180°.