We demonstrated efficient optical rectification in the organic crystal BNA (N-benzyl-2-methyl-4-nitroaniline), driven by a commercial industrial Yb laser system with time compression running at a repetition rate of 540 kHz.Our terahertz (THz) source achieves an average THz power of 5.6 mW, driven by 4.7 W, 45 fs pulses, resulting in a THz time-domain spectrum that combines a very wide bandwidth of 7.5 THz and a high dynamic range of 75 dB (measurement time of 70 seconds).The conversion efficiency at maximum terahertz power is 0.12%.To our knowledge, this is the highest terahertz power demonstrated so far using BNA, achieved at a high repetition rate, and capable of demonstrating a combination of bandwidth and dynamic range for terahertz spectroscopy applications.