Kevin King
Senior Manager, Electrical Design Engineer
Published: August 23, 2019

We continue to see major strides in highly integrated systems-on-chips (SoCs) and FPGAs from semiconductor makers like Xilinx. The high level of integration comes from ever-shrinking geometries as small as 7 nanometers on some of the newer devices. This comes at the cost of very complex power designs utilizing many power rails and at currents in the tens, if not hundreds, of amps.

An example of a typical Xilinx® Ultrascale™ design is shown in Figure 1. Looking at this block diagram, there are a total of 18 power rails for various portions of the system and the FPGA itself. If you inspect these rails, the range of operation, accuracy, and noise is very wide and diverse. The core voltage is 0.85VDC at a massive 125A, and HBM memory support is at 2.5VDC at 1A, and 3.3VDC at 500mA. So if you want to tackle this task, you will be required to design 18 different power supplies. The design of these power rails is complex, from both the initial schematics to the actual PCB recommendations. How do you manage these types of power densities and guarantee reliable operation?

Sometimes the best method is to utilize the “free engineering” available to you and use a reference design from Renesas, where all the heavy lifting has already been done for you.

The Renesas portfolio includes digital multiphase controllers, digital PoLs, multi-phase PMICs and discrete components to provide a highly integrated and scalable complete power solution. The solution shown provides great performance and reduced customer BOM cost. All of the discrete values of inductors and capacitors have been worked out for you. Thermal management issues and PCB layout examples have also been provided.

Renesas reference designs are great resources available for anyone to utilize and allow them to avoid most, if not all, of the tedious work of power supply design. 

So if you would like to focus on the function of your Xilinx FPGA design and less on the mundane work of getting the proper power rails to the device, learn more by visiting the FPGA Design page.

Visit the winning combinations page to see more winning combination solutions that help our customers accelerate their designs to get to market faster.

Figure 1. Xilinx® UltraScale+™ Winning Combo Design

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