I use a U3S QRP Labs exciter to drive a PA on 137kHz, and it works fine. The designers, Hans Summer made changes allowing a 180 out of phase pair of signals to come from the Si5351A synthesizer chip with the intention of this being able to drive a push pull Class D FET driver chip directly without a X2 signal being divided and split by a preceding IC, please see circuit below. I tried this but the circa 2.2V outputs of the Si5351A chip is not sufficient to drive the inputs of the IR2110 FET driver.
Any ideas please?