A time-to-digital converter has been developed for a gas filled detector with a delay line readout. It is based on a time interpolation method with a built-in master oscillator of 200 MHz. A resolution of 80 ps was achieved and the differential non linearity is less than +/- 1.5%. Also, a rate up to 3 MHz is possible. The circuit has a dynamic range of 16 bits and fed in a single width NIM format. The performance of the TDC and test results are given.