The TL851 is an economical digital I2L ranging control integrated circuit designed for use with the Texas Instruments TL852 sonar ranging receiver integrated circuit. The TL851 is designed for distance measurement from six inches to 35 feet. The device has an internal oscillator that uses a low-cost external ceramic resonator. With a simple interface and a 420-kHz ceramic resonator, the device will drive a 50-kHz electrostatic transducer. The device cycle begins when Initiate (INIT) is taken to the high logic level. There must be at least 5 ms from initial power-up (VCC) to the first initiate signal in order for all the device internal latches to reset and for the ceramic-resonator-controlled oscillator to stabilize. The device will transmit a burst of 16 pulses each time INIT is taken high.