I needed a high speed ADC for sampling in cylinder pressure for my ECU, and settled on trying a few from Texas Instruments. I am using an optical encoder on the engine which provides 720 pulses per revolution . If I took a sample every pulse, then at 6000 RPM (100 Hz) then I would be looking at about 720 * 100 Hz = 72,000 Samples per Second (SPS) or 72kHz ( although I realise now that I could take a sample on each edge, resulting in 1440 samples per revolution, or 144,000 SPS). That’s pretty high speed, considering most ADCs built into microcontrollers take a few microseconds to perform their conversion which results in a sampling rate of perhaps up to 50,000 SPS max for the Arduino for example. DSP chips or higher end micros probably have better performance, but for the sake of learning, I fancied trying to use an external ADC anyway.