Typical Field Programmable Gate Array (FPGA)
Power Requirements
The flexibility of FPGAs
leads to the requirement for multiple supply voltages and
currents.
Core Voltage/Power
In large FPGAs, the logic core generally has the most
demanding current requirements, up to tens of amps depending
on the number of gates being used and the clock frequency.
Designated VCCINT by Xilinx, by
platform the voltage required is:
Virtex®-II and Virtex-II Pro® series = 1.5V
Spartan-3 series = 1.2V
I/O Voltage/Power
Designated VCCO and equal to 1.5V,
1.8V, 2.5V or 3.3V depending on the I/O standard selected.
I/O standards can be set independently by block in the FPGA,
so more than one I/O voltage for a single FPGA is possible.
VAUX
Voltage/Power
The “auxiliary” supply is important for the latest
generation of Xilinx FPGAs because it is tied into the JTAG,
DCM, and other circuitry. It is designated VCCAUX
, and is usually 3.3V or 2.5V. VCCAUX
must be sufficiently decoupled in order to avoid power
supply transients coupling into the FPGA’s clock circuitry.
