This document discusses power supply design considerations for modern FPGAs, including output voltage requirements and specifications for different power rails. It provides voltage requirements and tolerances for some of the newest FPGAs.
The document provides design recommendations for powering modern FPGAs, covering voltage requirements, sequencing, soft‑start, and transient response. It highlights how National Semiconductor’s LM series devices can meet the demanding voltage, current, and timing specifications of FPGA core, I/O and auxiliary rails.
Application examples illustrate typical schematics using the LM3880 sequencer, LMZ14203 and LMZ10504 SIMPLE SWITCHER modules, and the LM26480 PMIC. The guide also discusses fault protection features, voltage‑tracking techniques, and best practices for monotonic startup and pre‑biased conditions.
| LMZ14203 fault protection | OVP, UVP, thermal shutdown, accurate current limit |
|---|---|
| LMZ10504 efficiency | up to 96% |
| LMZ10504 switching frequency | fixed 1 MHz |
| LM20125 current capability | 5 A |
A startup time of about 10 ms generally limits capacitive inrush currents while meeting FPGA requirements.
The LM3880 provides sequential sequencing of multiple supply rails and can control up to three rails in a small SOT‑23 package.