The TDC7201 is designed for use with ultrasonic, laser and radar range finding equipment using time-of-flight technique. The TDC7201 has two built-in Time-to-Digital Converters (TDCs) that can be used to measure distance down to 4 cm and up to several kilometers using a simple architecture, which eliminates the need to use expensive FPGAs or processors. Each TDC performs the function of a stopwatch and measures the elapsed time (time-of-flight or TOF) between a START pulse and up to five STOP pulses. The ability to measure simultaneously and individually on two pairs of START and STOP pins using two built-in TDCs offers high flexibility in time measurement design. The device has an internal self-calibrated time base which compensates for drift over time and temperature. Self-calibration enables time-to-digital conversion accuracy in the order of picoseconds. This accuracy makes the TDC7201 ideal for range finder applications. When placed in the Autonomous Multi-Cycle Averaging Mode, the TDC7201 device can be optimized for low system power consumption, which is ideal for battery-powered flow meters. In this mode, the host can go to sleep to save power and wake up when interrupted by the TDC upon completion of the measurement sequence.