  RF system-on-chip (RFSoC) devices provide the potential for implementing a
complete radio astronomy receiver on a single board, but performance of the
integrated analogue-to-digital converters is critical. We have evaluated the
performance of the data converters in the Xilinx ZU28DR RFSoC, which are
12-bit, 8-fold interleaved converters with a maximum sample speed of 4.096
Giga-sample per second (GSPS). We measured the spurious-free dynamic range
(SFDR), signal-to-noise and distortion (SINAD), effective number of bits
(ENOB), intermodulation distortion (IMD) and cross-talk between adjacent
channels over the bandwidth of 2.048 GHz. We both captured data for off-line
analysis with floating-point arithmetic, and implemented a real-time integer
arithmetic spectrometer on the RFSoC. The performance of the ADCs is sufficient
for radio astronomy applications and close to the vendor specifications in most
of the scenarios. We have carried out spectral integrations of up to 100 s and
stability tests over tens of hours and find thermal noise-limited performance
over these timescales.
