This paper describes a high voltage pulser developed for an air-coupled ultrasonic array NDE system based on Lamb waves. Unlike the classical single pulse excitation circuits, this pulser is able to generate a bipolar return-to-zero square-wave burst signal up to ±250 V of amplitude. The system is composed of two 32 elements concave array with a resonant frequency of 800 kHz. To excite all the transducers an array of pulsers with small volume and weight to be able to place it close to the concave array has been designed.