48
www.xilinx.com
ML365 Virtex-II Pro QDR II SRAM Mem. Board
1-800-255-7778
UG066 (v1.0) June 29, 2004
Chapter 5:
Board Layout Guidelines
R
Providing Additional Ground Pins
Unused and No Connect pinscan be connected to ground to improve the thermal
dissipation through the metal planes in the Printed Circuit Board. Since DCI can be used in
the FPGA, the heat resulting from its use can be significant.
VAUX 2.5V
1 capacitor per
pin, in a
balanced
decoupling
network.
0.01
µ
F ceramic capacitor, X7R, C0402
31
0.047
µ
F ceramic capacitor, X7R , C0603
14
2.2
µ
F ceramic capacitor, X7R, C1206
7
33
µ
F ceramic capacitor, 10V, C7343
4
330
µ
F solid tantalum capacitor, 10V, C7343
2
VCCO 1.8V
HSTL 1.8V
electrical
standard
0.01
µ
F ceramic capacitor, X7R, C0402
76
0.047
µ
F ceramic capacitor, X7R , C0603
38
2.2
µ
F ceramic capacitor, X7R, C1206
23
33
µ
F ceramic capacitor, 10V, C7343
9
330
µ
F solid tantalum capacitor, 10V, C7343
7
VCCINT 1.5V
1 capacitor per
pin, in a
balanced
decoupling
network.
0.01
µ
F ceramic capacitor, X7R, C0402
30
0.047
µ
F ceramic capacitor, X7R , C0603
11
2.2
µ
F ceramic capacitor, X7R, C1206
11
33
µ
F ceramic capacitor, 10V, C7343
8
330
µ
F solid tantalum capacitor, 10V, C7343
6
VTT 0.9V
HSTL 1.8V/2
for FPGA Vref
inputs
0.01
µ
F ceramic capacitor, X7R, C0402
5
0.047
µ
F ceramic capacitor, X7R , C0603
1
2.2
µ
F ceramic capacitor, X7R, C1206
4
33
µ
F ceramic capacitor, 10V, C7343
0
330
µ
F solid tantalum capacitor, 10V, C7343
0
VTT 0.9V
HSTL 1.8V/2
for memory
Vref inputs
0.01
µ
F ceramic capacitor, X7R, C0402
13
0.047
µ
F ceramic capacitor, X7R , C0603
9
2.2
µ
F ceramic capacitor, X7R, C1206
0
33
µ
F ceramic capacitor, 10V, C7343
0
330
µ
F solid tantalum capacitor, 10V, C7343
0
Table 5-1:
Decoupling Capacitor Recommendations
Decoupling
Capacitors
Pin(s)
Capacitor Value
Distribution
Product Not Recommended for New Designs