Configuration via Protocol (CvP) Implementation in V-series FPGA Devices User Guide

ID 683889
Date 9/04/2020
Public
Document Table of Contents

4.2.1. FPGA Power Supplies Ramp Time Requirement

For an open system, you must ensure that your design adheres to the FPGA power supplies ramp-up time requirement.

The power-on reset (POR) circuitry keeps the FPGA in the reset state until the power supply outputs are in the recommended operating range. A POR event occurs from when you power up the FPGA until the power supplies reach the recommended operating range within the maximum power supply ramp time, tRAMP . If tRAMP is not met, the device I/O pins and programming registers remain tri-stated, during which device configuration could fail.

For CvP, the total tRAMP must be less than 10 ms, from the first power supply ramp-up to the last power supply ramp-up. You must select fast POR by setting the PORSEL pin to high. The fast POR delay time is in the range of 4–12 ms, allowing sufficient time after POR for the PCIe link to start initialization and configuration.

Figure 8. Power Supplies Ramp-Up Time and POR