I am using the trying to evaluate the LT3572 using the DC1197A evaluation board. I have powered it using an external DC lab power supply at 3.3 volts. I have a Sigilent arbitrary function generator providing a 50% 800 kHz 0 to 2V square wave signal between the PWMA and GND pin closest to the PWMA pin. I measure 30V output across the Vout and Gnd pin. When I try to measure the signal at the Out A pin (either the positive or negative out pin) by placing a digital oscilloscope probe between GND and OUT A I am not seeing a 800 kHz signal, I am just seeing noise and hearing a buzzing. The same holds true if change to the PWMB and OutB pins.
Any suggestions? Does this dev board actually need to be connected to a piezo or other load? Could there be an issue with the DC power supply, oscilloscope, and the function generator all connected to various ground pins on the demo board?