The Jiangmen Underground Neutrino Observatory (JUNO) is a multi-purpose experiment with the neutrino mass hierarchy determination as main objective. The signal detection is based on a 20 kt liquid scintillator surrounded by photomultipliers (PMTs) that are read out with electronics close to them. A highly integrated analog to digital conversion unit with low power and large dynamic range is developed in 65 nm CMOS to be integrated into the PMT housing. Due to the inaccessibility of the electronics, low failure rate has to be achieved. A rigorous production test strategy is developed and presented here to increase the test coverage and effectively eliminate the expected failure rate in the experiment's runtime. This work also gives an overview of the features and some recent measurement results from the second generation of the readout chip.