Xilinx Virtex-5 User Manual download pdf (Page 56)

56 www.xilinx.com Virtex-5 FPGA ML561 User Guide

UG199 (v1.2) April 19, 2008

Chapter 7: ML561 Hardware-Simulation Correlation

illustrated here for these signals can be easily adopted to perform SI analysis for any other

memory interface signal on the ML561 board.

This chapter presents the SI results for the following six data bit signals:

• DDR2 component DQ bit (DDR2_DQ_BY2_B3) for write operations

• DDR2 component DQ bit (DDR2_DQ_BY2_B3) for read operations

• DDR2 DIMM DQ bit (DDR2_DIMM_DQ_BY2_B3) for write operations

• DDR2 DIMM DQ bit (DDR2_DIMM_DQ_BY2_B3) for read operations

• QDRII D bit (QDR2_D_BY0_B5) for write operations

• QDRII Q bit (QDR2_Q_BY0_B5) for read operations

Test Setup

Hardware measurements were performed for the six specific signal nets, and then signal

integrity (SI) simulations were performed for correlation and extrapolation. The test setup

consisted of the following hardware equipment, simulation software tools, the stimulus

test pattern, and test criteria for determining the quality of signals. The test bench is

designed so that the test pattern is applied only to the signal under test, and all other data

bits to the same memory interface are kept in a quiet Low state. This setup ensures that the

hardware measurement is not altered due to any simultaneous switching output (SSO)

effect.

• Hardware measurement equipment

♦ Agilent DSO80604B 6 GHz oscilloscope

♦ Agilent 1131A 3.5 GHz Infiniimax probe amplifier

♦ Agilent E2675A (Differential browser) or E2677A (Differential solder-in probe) or

N5425A (ZIF probe)

♦ Virtex-5 FPGA ML561, Rev B2 board: S/N 103

♦ SRS Model CG635 Synthesized Clock Generator for low jitter clock source

• Simulation software

♦ Mentor Graphics HyperLynx EXT, Version 7.5 with LineSim and BoardSim

features

♦ Xilinx Virtex-5 FPGA IBIS package file: ff1136_5vlx50t.pkg, Rev 1.0 dated

June 12, 2006

♦ ML561, Rev B layout file: ML561_B_041706.hyp

♦ Micron DDR2-667 IBIS model for output and ODT input

♦ Micron PC2-5300 RDIMM IBIS model

♦ Molex DDR2 DIMM socket specification (P/N 087705-1041)

♦ Samsung QDRII HSTL 1.8V IBIS model

♦ IBISWriter Utility of ISE software suite to create customized IBIS model of the

FPGA1 (U7) and FPGA3 (U34) devices on the ML561 board: Model files

ml561_fpga1_u7.ibs and ml561_fpga3_u34.ibs. (See “How to Generate a

User-Specific FPGA IBIS Model,” page 93 for steps on how to create a customized

IBIS model of Virtex-5 FPGA for your design.)

• Stimulus

Pseudo Random Bit Stream (PRBS) is accepted as the most effective test pattern to

measure the quality of data signals because, unlike the periodic signals like clock and

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