XC4VFX12-11FFG668C Xilinx Inc, XC4VFX12-11FFG668C Datasheet - Page 237

• Manufacturer Part Number: XC4VFX12-11FFG668C
• Description: IC FPGA VIRTEX-4 FX 12K 668FCBGA
• Manufacturer: Xilinx Inc
• Series: Virtex™-4r

Specifications of XC4VFX12-11FFG668C

• Number Of Logic Elements/cells: 12312
• Number Of Labs/clbs: 1368
• Total Ram Bits: 663552
• Number Of I /o: 320
• Voltage - Supply: 1.14 V ~ 1.26 V
• Mounting Type: Surface Mount
• Operating Temperature: 0°C ~ 85°C
• Package / Case: 668-BBGA, FCBGA
• For Use With: HW-V4-ML403-UNI-G - EVALUATION PLATFORM VIRTEX-4HW-AFX-FF668-400 - BOARD DEV VIRTEX 4 FF668
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Number Of Gates: -

Virtex-4 FPGA User Guide
UG070 (v2.6) December 1, 2008
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Controlled Impedance Driver (Source Termination)
Controlled Impedance Driver with Half Impedance (Source Termination)
The coarse impedance calibration during first phase of impedance adjustment can be
invoked after configuration by instantiating the DCIRESET primitive. By toggling the RST
input to the DCIRESET primitive while the device is operating, the DCI state machine is
reset and both phases of impedance adjustment proceed in succession. All I/Os using DCI
will be unavailable until the LOCKED output from the DCIRESET block is asserted.
This functionality is useful in applications where the temperature and/or supply voltage
changes significantly from device power-up to the nominal operating condition. Once at
the nominal operating temperature and voltage, performing the first phase of impedance
adjustment allows optimal headroom for the second phase of impedance adjustment.
For controlled impedance output drivers, the impedance can be adjusted either to match
the reference resistors or half the resistance of the reference resistors. For on-chip
termination, the termination is always adjusted to match the reference resistors.
DCI can configure output drivers to be the following types:
1.
2.
It can also configure inputs to have the following types of on-chip terminations:
1.
2.
For bidirectional operation, both ends of the line can be DCI-terminated permanently:
1.
2.
Alternatively, bidirectional point-to-point lines can use controlled-impedance drivers
(with 3-state buffers) on both ends.
Some I/O standards, such as LVCMOS, must have a drive impedance matching the
characteristic impedance of the driven line. DCI can provide controlled impedance output
drivers to eliminate reflections without an external source termination. The impedance is
set by the external reference resistors with resistance equal to the trace impedance.
The DCI I/O standards supporting the controlled impedance driver are: LVDCI_15,
LVDCI_18, LVDCI_25, LVDCI_33, HSLVDCI_15, HSLVDCI_18, HSLVDCI_25, and
HSLVDCI_33.
DCI also provides drivers with one half of the impedance of the reference resistors. This
doubling of the reference resistor value reduces the static power consumption through
Controlled Impedance Driver (Source Termination)
Controlled Impedance Driver with Half Impedance (Source Termination)
Input termination to V
Input termination to V
Driver with termination to V
Driver with termination to V
Figure 6-4
Figure 6-4: Controlled Impedance Driver
illustrates a controlled impedance driver in a Virtex-4 device.
www.xilinx.com
CCO
CCO
Virtex-4 FPGA DCI
/2 (Split Termination, Thevenin equivalent)
(Single Termination)
CCO
CCO
SelectIO Technology Resources General Guidelines
R
/2 (Split Termination, Thevenin equivalent)
(Single Termination)
IOB
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