Xilinx has just introduced a totally new technology for high-speed RF designs: an integrated RF-processing subsystem consisting of RF-class ADCs and DACs implemented on the same piece of 16nm UltraScale+ silicon along with the digital programmable-logic, microprocessor, and I/O circuits. This technology transforms the All Programmable Zynq UltraScale+ MPSoC into an RFSoC. The technology’s high-performance, direct-RF sampling simplifies the design of all sorts of RF systems while cutting power consumption, reducing the system’s form factor, and improving accuracy—driving every critical, system-level figure of merit in the right direction.
The fundamental converter technology behind this announcement was recently discussed in two ISSCC 2017 papers by Xilinx authors: “A 13b 4GS/s Digitally Assisted Dynamic 3-Stage Asynchronous Pipelined-SAR ADC” and “A 330mW 14b 6.8GS/s Dual-Mode RF DAC in 16nm FinFET Achieving -70.8dBc ACPR in a 20MHz Channel at 5.2GHz.” (You can download a PDF copy of those two papers here.)
This advanced RF converter technology vastly extends the company’s engineering developments that put high-speed, on-chip analog processing onto Xilinx All Programmable devices starting with the 1Msamples/sec XADC converters introduced on All Programmable 7 series devices way back in 2012. However, these new 16nm RFSoC converters are much, much faster—by more than three orders of magnitude. Per today’s technology announcement, the RFSoC’s integrated 12-bit ADC achieves 4Gsamples/sec and the integrated 14-bit DAC achieves 6.4Gsamples/sec, which places Xilinx RFSoC technology squarely into the arena for 5G direct-RF design as well as millimeter-wave backhaul, radar, and EW applications.
Here’s a block diagram of the RFSoC’s integrated RF subsystem:
Xilinx Zynq UltraScale+ RFSoC RF Subsystem
In addition to the analog converters, the RF Data Converter subsystem includes mixers, a numerically controlled oscillator (NCO), decimation/interpolation, and other DSP blocks dedicated to each channel. The RF subsystem can handle real and complex signals, required for IQ processing. The analog converters achieve high sample rates, large dynamic range, and the resolution required for 5G radio-head and backhaul applications. In some cases, the integrated digital down-conversion (DDC) built into the RF subsystem requires no additional FPGA resources.
The end result is breakthrough integration. The analog-to-digital signal chain, in particular, is supported by a hardened DSP subsystem for flexible configuration by the analog designer. This leads to a 50-75% reduction in system power and system footprint, along with the needed flexibility to adapt to evolving specifications and network topologies.
Where does that system-power reduction come from? The integration of both the digital and analog-conversion electronics on one piece of silicon eliminates a lot of power-hungry I/O and takes the analog converters down to the 16nm FinFET realm. Here’s a power-reduction table from the backgrounder with three MIMO radio example systems:
How about the form-factor reduction? Here’s a graphical example:
You save the pcb space needed by the converters and you save the space required to route all of the length-matched, serpentine pcb I/O traces between the converters and the digital SoCs. All of that I/O connectivity and the length matching now takes place on-chip.
To learn more about the All Programmable RFSoC architecture, click here or contact your friendly, neighborhood Xilinx sales representative.
Note: When we say “All Programmable” we mean it.