Digilent 410-044-10P-KIT User Manual
Page 46
46
Spartan-3 Starter Kit Board User Guide
1-800-255-7778
UG130 (v1.1) May 13, 2005
Chapter 12: Power Distribution
R
2.5V and 1.2V regulators. Similarly, the 3.3V regulator feeds all the V
CCO
voltage supply
inputs to the FPGA’s I/O banks and powers most of the components on the board.
The 2.5V regulator supplies power to the FPGA’s V
CCAUX
supply inputs. The V
CCAUX
voltage input supplies power to Digital Clock Managers (DCMs) within the FPGA and
supplies some of the I/O structures. In specific, all of the FPGA’s dedicated configuration
pins, such as DONE, PROG_B, CCLK, and the FPGA’s JTAG pins, are powered by V
CCAUX
.
The FPGA configuration interface on the board is powered by 3.3V. Consequently, the 2.5V
supply has a current shunt resistor to prevent reverse current.
Finally, a 1.2V regulator supplies power to the FPGA’s V
CCINT
voltage inputs, which
power the FPGA’s core logic.
The board uses three discrete regulators to generate the necessary voltages. However,
various power supply vendors are developing integrated solutions specifically for
Spartan-3 FPGAs.
provides a detailed schematic of the various voltage regulators. Similarly,
shows the power decoupling capacitors.