Signal Integrity and PCB layout considerations for DDR2-800 Mb/s ...

DDR2 and DDR3 NetsCDNLive 2007! Silicon Valley 2

PCB Layer Stackup and ImpedanceCDNLive 2007! Silicon Valley 4

Interconnect Topologies (ADDR/CMD/CNTRL)CDNLive 2007! Silicon Valley 5

Interconnect Topologies (ADDR/CMD/CNTRL)CDNLive 2007! Silicon Valley 6

DELAY MATCHINGTrombone traceStraight traceL 1 + L 2 + L 3 + L 4 + L 5≠L 1L 2L 3L 4L 5Via cross sectional viewStraight traceL 1≠L 2L 3L 1 + L 2 + L 3CDNLive 2007! Silicon Valley 7

TROMBONE DELAY SIMULATIONCDNLive 2007! Silicon Valley 8

VIA effect on DELAYCDNLive 2007! Silicon Valley 9

Cross talkCDNLive 2007! Silicon Valley 10

Power IntegrityCDNLive 2007! Silicon Valley 11

TIMING1. Write Setup analysis DQ vs. DQS2. Write Hold analysis DQ vs. DQS3. Read Setup analysis DQ vs. DQS4. Read Hold analysis DQ vs. DQS5. Write Setup analysis DQS vs. CLK*6. Write Hold analysis DQS vs. CLK*7. Write Setup analysis Address/CMD/CNTRL vs. CLK8. Write Hold analysis Address/CMD/CNTRL vs. CLK* Write Leveling in DDR3 eliminates the need for 5 and 6CDNLive 2007! Silicon Valley 12

TIMING SummaryCDNLive 2007! Silicon Valley 13

PCB Layout1. Controller BGA Breakout2. Topology for ADDR/CMD/CNTRL3. Decoupling capacitor placement and low inductance foot print.CDNLive 2007! Silicon Valley 14

PCB Layout continued4. Fine tuning and ground viasCDNLive 2007! Silicon Valley 15

DDR3 LAYOUT ExampleCDNLive 2007! Silicon Valley 16

DDR3 Waveforms (1600 Mbps)CDNLive 2007! Silicon Valley 17

DDR2 LayoutCDNLive 2007! Silicon Valley 18

DDR2 Waveforms (800 Mbps)CDNLive 2007! Silicon Valley 19

DDR3 – DIMM LAYOUTCDNLive 2007! Silicon Valley 20

DDR3 – DIMM Waveforms (1600 Mbps) at 8 th SDRAM on DIMMCDNLive 2007! Silicon Valley 21

Conclusion1. Main DDR2/DDR3 implementation details have been presented2. ALLEGRO CM usage eases Layout3. 800 Mbps operation on a 4 layer PCB √4. 1600 Mbps DDR3 on a 4 layer PCB ?For more information:Syed Bokhari Tel: 613-828-0063 Ext: 377 Syed.Bokhari@fidus.caAbout Fidus:Fidus Systems Inc. develops electronic products for a wide range of industries including;telecommunications, aerospace and defence, video, transportation and automotiveapplications, storage and memory, consumer products, biomedical instrumentation andindustrial controls. Fidus specializes in complete, turn-key product development, ortargeted design of architecture, hardware, FPGA, RF, software/firmware, circuit boardlayout, signal integrity and EMC analysis. Fidus has consulted on more than 500 rightfirst-timeprojects for customers across North America and Europe. For moreinformation, please visit www.fidus.comCDNLive 2007! Silicon Valley 22