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66 www.xilinx.com ML361 Virtex-II Pro Memory Board
UG060 (v1.2) November 8, 2007
Chapter 5: Board Layout Guidelines
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Table 5-2 lists the decoupling capacitors for the DDR SDRAMs.
Table 5-3 lists the decoupling capacitors for the DDR DIMM.
Bank 2
VREF
7 VREFs used, one capacitor for each VREF
0.039 µF ceramic capacitor, 0402 10V X7R –20/+20% 2
0.22 µF ceramic capacitor, 0603 10V X7R –20/+20% 1
1 µF ceramic capacitor, 0603 6V X7R –20/+20% 1
330 µF solid tantalum capacitor, 6.3V 1, shared with bank 3
Bank 3 Same as Bank 2 for both I/Os and VREFs
Bank 6 Same as Bank 2 for both I/Os and VREFs
Bank 7 Same as Bank 2 for both I/Os and VREFs
Bank 1
1 Reset,
8 GPIO,
4 LED,
8 DIP,
14 DISPLAY
0.033 µF ceramic capacitor, 0402 6V X7R –20/+20% 1
0.22 µF ceramic capacitor, 0603 6V X7R –20/+20% 1
1 µF ceramic capacitor, 0603 6V X7R –20/+20% 1
330 µF solid tantalum capacitor, 6.3V 1
Bank 0 Similar to Bank 1
Bank 4 Similar to Bank 1
Bank 5 Similar to Bank 1
Table 5-1: FPGA Decoupling Capacitors (Cont’d)
Pin(s) Capacitor Value Distribution
Table 5-2: DDR SDRAM Decoupling Capacitors
Pin(s) Capacitor Value Quantity Distribution
VDD,
VDDQ,
VREF, VSS,
VSSQ
0.01 µF ceramic capacitor, 0402 6V X7R –20/+20% 8 1 capacitor per pin, in a
balanced decoupling network.
17 total for each component
0.1 µF ceramic capacitor, 0603 6V X7R –20/+20% 8
330 µF solid tantalum capacitor, 6.3V 1
Table 5-3: DIMM Decoupling Capacitors
Pin(s) Capacitor Value Distribution
VDD 0.01 µF ceramic capacitor, 0402 6V X7R –20/+20% 1 per VDD pin
0.1 µF ceramic capacitor, 0603 6V X7R –20/+20% 1 per VDD pin
330 µF solid tantalum capacitor, 6.3V 1
VDDQ 0.01 µF ceramic capacitor, 0402 6V X7R –20/+20% 1 per VDDQ pin
0.1 µF ceramic capacitor, 0603 6V X7R –20/+20% 1 per VDDQ pin
330 µF solid tantalum capacitor, 6.3V 2