XCV405E-7BG560I Xilinx Inc, XCV405E-7BG560I Datasheet - Page 24

• Manufacturer Part Number: XCV405E-7BG560I
• Description: IC FPGA 1.8V 560-MBGA
• Manufacturer: Xilinx Inc
• Series: Virtex™-E EMr

Specifications of XCV405E-7BG560I

• Number Of Logic Elements/cells: 10800
• Number Of Labs/clbs: 2400
• Total Ram Bits: 573440
• Number Of I /o: 404
• Number Of Gates: 129600
• Voltage - Supply: 1.71 V ~ 1.89 V
• Mounting Type: Surface Mount
• Operating Temperature: -40°C ~ 100°C
• Package / Case: 560-LBGA, Metal
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Virtex™-E 1.8 V Extended Memory Field Programmable Gate Arrays
Design Considerations
This section contains more detailed design information on
the following features.
•
•
•
Using DLLs
The Virtex-E FPGA series provides up to eight fully digital
dedicated on-chip Delay-Locked Loop (DLL) circuits which
provide zero propagation delay, low clock skew between
output clock signals distributed throughout the device, and
advanced clock domain control. These dedicated DLLs can
be used to implement several circuits which improve and
simplify system level design.
Introduction
As FPGAs grow in size, quality on-chip clock distribution
becomes increasingly important. Clock skew and clock
delay impact device performance and the task of managing
clock skew and clock delay with conventional clock trees
becomes more difficult in large devices. The Virtex-E series
of devices resolve this potential problem by providing up to
eight fully digital dedicated on-chip DLL circuits which pro-
vide zero propagation delay and low clock skew between
output clock signals distributed throughout the device.
Each DLL can drive up to two global clock routing networks
within the device. The global clock distribution network min-
imizes clock skews due to loading differences. By monitor-
ing a sample of the DLL output clock, the DLL can
compensate for the delay on the routing network, effectively
eliminating the delay from the external input port to the indi-
vidual clock loads within the device.
In addition to providing zero delay with respect to a user
source clock, the DLL can provide multiple phases of the
source clock. The DLL can also act as a clock doubler or it
can divide the user source clock by up to 16.
Clock multiplication gives the designer a number of design
alternatives. For instance, a 50 MHz source clock doubled
by the DLL can drive an FPGA design operating at 100
MHz. This technique can simplify board design because the
clock path on the board no longer distributes such a
high-speed signal. A multiplied clock also provides design-
ers the option of time-domain-multiplexing, using one circuit
twice per clock cycle, consuming less area than two copies
of the same circuit. Two DLLs in can be connected in series
to increase the effective clock multiplication factor to four.
The DLL can also act as a clock mirror. By driving the DLL
output off-chip and then back in again, the DLL can be used
to de-skew a board level clock between multiple devices.
Module 2 of 4
20
Delay-Locked Loop . . . see
BlockRAM . . . see
SelectI/O . . . see
page 31
page 24
page 20
www.xilinx.com
1-800-255-7778
In order to guarantee the system clock establishes prior to
the device “waking up,” the DLL can delay the completion of
the device configuration process until after the DLL
achieves lock.
By taking advantage of the DLL to remove on-chip clock
delay, the designer can greatly simplify and improve system
level design involving high-fanout, high-performance clocks.
Library DLL Symbols
Figure 21
symbol, BUFGDLL. This macro delivers a quick and effi-
cient way to provide a system clock with zero propagation
delay throughout the device.
the two library DLL primitives. These symbols provide
access to the complete set of DLL features when imple-
menting more complex applications.
Figure 21: Simplified DLL Macro Symbol BUFGDLL
Figure 22: Standard DLL Symbol CLKDLL
Figure 23: High Frequency DLL Symbol
shows the simplified Xilinx library DLL macro
I
CLKIN
CLKFB
RST
0ns
CLKIN
CLKFB
RST
CLKDLLHF
CLKDLL
DS025-2 (v2.3) November 19, 2002
Figure 22
CLK0
CLK90
CLK180
CLK270
CLK2X
CLKDV
LOCKED
CLK0
CLK180
CLKDV
LOCKED
ds022_25_121099
ds022_26_121099
ds022_027_121099
O
and
Figure 23
show
R