Breakthrough Insight into DDR4/LPDDR4 Memory Greater Than 2400 Mb/s

Transcription

1 Breakthrough Insight into DDR4/LPDDR4 Memory Greater Than 2400 Mb/s January 2015 Jennie Grosslight Product Manager

2 Agenda Overview Benefits and challenges for DDR4 and LPDDR4 >2400Mb/s Breakthrough Insight Gained from Logic Analyzer Techniques to address debug and validation challenges DDR Eye Scan insight DDR4 >3.1 Gb/s DIMM system - Tuning tool - Waveforms and Burst Trigger - View Initialization - Follow the initialization signal flow - Compliance and Performance Tools Successful logic analyzer probing techniques for higher data rates DDR Solution Overview, Recommendations, & Q&A Page 2

3 DDR4 and LPDDR4 Benefits DDR4 Benefits Up to 30-40% power savings over DDR3 More power control (power savings and reliability improvement) Targeting 3.2Gbps data rate (possibly higher improves bandwidth) Higher density (double # of banks) More error checking (improves reliability) Lower price than LPDDR3 (this will make DDR4 attractive to some mobile applications). LPDDR4 Benefits Up to 40% power efficiency over DDR4 & greater than 40% over LPDDR3 in standby LVSTL interface with VSSQ termination Enables data rates over 3.2Gb/s Increases bandwidth per pin Single Data Rate CA signals = easier to maintain good signal integrity Page 3

4 DDR4 and LPDDR4 Design Challenges How will I maximize the benefits? Faster data rates and smaller signal swings Extreme space constraints New protocols with new features require new memory controllers Memory controllers must be smarter Power management features need to be understood to optimize systems. Risk that systems will not behave as designed Maintaining signal integrity at higher data rates with smaller signal swings is a significant challenge Page 4

5 Capturing DDR4 and LPDDR4 at Higher Data Rates DQ capture over 2400Mb/s is particularly challenging Data Rate (Mb/s) LPDDR Majority new designs will be in this range DDR4 DDR Mb/s 1500 LPDDR Page 5

6 Data Rate DDR4 and LPDDR4 Challenges Data Valid Windows Shrinking Data Rates Increasing Signal swing decreasing Signal integrity variations between systems Read DDR Read DDR Read DDR DDR4 3120, 2400 and 1600 eyes were less than 200mV at the DDR4 interposer! Read DDR Data valid windows scanned on U4154B logic analyzers with FS2510 DDR4 DIMM interposer on different DDR4 targets Page 6

7 Breakthrough capture of DDR4 or LPDDR4 at highest data rates Proven DDR4 capture >3.1Gb/s Proven LPDDR4 capture at 3.2Gb/s U4154B system configuration for DDR4 DIMM capture over 2.5Gb/s: 3 modules M9505A chassis M9536A embedded controller FS2510 DDR4 DIMM Interposer (with FS1070 kit for DDR4 > 2.5Gb/s) U4154B system configurations vary for DDR2/3/4 and LPDDR/2/3/4 technologies and probing use models. Page 7

8 Insight Gained from Logic Analyzer Timing modes See when events happen Asynchronous to system under test High Resolution is most useful >2400Mb/s State mode Follow signal flow see what happened Synchronous to clock from system Enables most powerful SW tools DDR eye scan mode eye diagrams Unique qualified views of all ADD/CMD/DQ/DQS Page 8 Sept 18, 2012

9 Benefit: Highest Confidence in Measurement Accuracy Superior Insight into Bus Level Signal Integrity Quickly view signals relative to each other Complete view of address and data lines Bus Level Signal Integrity Insight Overlay mode Signal Trace Mode Capture data valid windows 100 ps by 100 mv Page 9

10 Validate and Debug DDR3/4 or LPDDR3/4 Powerful system for test and validation High Resolution around trigger event Timing Zoom State Mode functional Validation Synchronous to clock in system under test Up to 200M deep traces Industry deepest logic analyzer trace on DDR/LPDDR data State Waveforms Page 10

11 Achieve Greater Insight Faster Full Suite of Software Productivity Tools Compliance Testing DDR2/3/4 and LPDDR/2/3/4 System Performance Analysis DDR2/3/4 and LPDDR/2/3/4 Real Time and Custom Violation Measurements Memory and General Purpose Applications DDR and LPDDR Decoder Tools Protocol Decoding and Insight State Waveforms Page 11

12 Insight Gained from Logic Analyzer LPDDR4 - Speed Change Active 1-2 sequence Clock turns on for 6 cycles before CKE enabled CA, BA, DQ, and DQS low unless driven high LPDDR4 Timing Zoom waveform entering slower speed Page 12

13 Insight Gained from Logic Analyzer Follow the LPDDR4 signal flow Decoder output from State mode trace in listing view Active 1-2 sequence Data captured on rising and falling edges when over 2.5Gb/s Row and Column address decoded Data Burst of 16 Page 13

14 Agenda Overview Benefits and challenges for DDR4 and LPDDR4 >2400Mb/s Breakthrough Insight Gained from Logic Analyzer Techniques to address debug and validation challenges DDR Eye Scan insight DDR4 >3.1 Gb/s DIMM system - Tuning tool - Waveforms and Burst Trigger - View Initialization - Follow the initialization signal flow - Compliance and Performance Tools Successful logic analyzer probing techniques for higher data rates DDR Solution Overview, Recommendations, & Q&A Page 14

15 Challenge: Eye openings on DDR4 > 3.1Gb/s Eye Scan Insight: Potential ODT setting issue. Threshold of first bit in burst has less swing than remainder of burst. Could also be ISI (inter-symbol interference) Overdriving DDR4 DRAM to 1.4V could cause damage. Next Steps: Take trace to inspect ODT operation Cross trigger scope to check for ISI Page 15

16 Challenge: System Signal Integrity DDR4 >3.1Gb/s DIMM system Eye Scan Insight: DQS2 has less swing than other DQS Next Steps: Check DQS DRAM drive strength, termination and trace routing Page 16

17 Challenge: Achieving Correct Signal Transitions Symptom: Data Corruption on DDR4 system Eye Scan Insight DDR4 Bank group 1 Transitioning incorrectly Next Steps: SW work around: Do not use BG1 = 1 Limits address space Long term: HW fix required Page 17

18 Challenge: Strobe Alignment Symptom: Data corruption on LPDDR3 system Eye Scan Insights: DQS2 & DQS3 not in alignment with DQS0 & DQS1 DQS3 pre-amble is wrong, low to high instead of High to low. Eye Scan Settings: Burst Scan, No back-to-back Next Steps: Check driver circuitry and Page SW January 2014

19 Challenge: Setting up measurements quickly Tuning tool DDR Setup Assistant Used DDR setup assistant with 10 simple steps to setup State mode measurements Page 19

20 Challenge: Triggering on sequential events at high speeds DDR4 > 3.1Gbps Waveforms and Burst Trigger (TZ) in label designates Timing Zoom, High resolution Timing waveforms State waveforms - Rising & Falling edge samples DQ 7-0 Page 20

21 Challenge: Capturing initialization sequences Example: DDR4 >3.1Gb/s Initialization 4M State Waveform, initialization sequence Trigger stores only valid commands and enough samples after a Read or Write to capture data bursts. Page 21

22 Capturing System Initialization continued Follow the initialization signal flow of DDR4 3.2Gb/s system Page 22

23 Challenge: Functional Compliance Testing Compliance and Performance Tools Compliance Tools Post process Real time Performance Analysis Provides bus statistic information. Provides histogram view on number of access at a specific memory address Page 23

24 Agenda Overview Benefits and challenges for DDR4 and LPDDR4 >2400Mb/s Breakthrough Insight Gained from Logic Analyzer Techniques to address debug and validation challenges DDR Eye Scan insight DDR4 >3.1 Gb/s DIMM system - Tuning tool - Waveforms and Burst Trigger - View Initialization - Follow the initialization signal flow - Compliance and Performance Tools Successful logic analyzer probing techniques for higher data rates DDR Solution Overview, Recommendations, & Q&A Page 24

25 Proven Probing Techniques to Capture Highest Data Rates Industry standard interposers = Designed and available! DDR4 DIMM interposer DDR4 SODIMM Interposer DDR4 x4/x8 BGA interposer User designs probing into system under test Follow Design guidelines! Specialty probing from Keysight Joint technical effort to meet specific needs Run simulations! Soft Touch Pro Mid-Bus Probing LPDDR3 POP interposer MemCon Page 25

26 DDR4 Interposers FS2510 Proven DDR4 >3.1Gb/s simultaneous Read and Write capture with FS1070 conversion kit Ease of connection Direct connect to U4154B Low profile - Minimal loading FS2510: DDR4 DIMM interposer Support UDIMM or RDIMM Timing and State analysis Support DDR Setup Assistant and DDR Eye Scan FS2512B: DDR SODIMM interposer Page 26

27 DDR4 x4/x8 BGA Interposer W4633A Designed for DDR4 < and > 2400 Three flex wings: Bend up to 180 deg Recommended bend radius of 1.27MM if flex is bent at rigid portion of interposer ZIF doors and GND plane on back side of wings Requires two E5849A DDR4 ZIF cables MemCon Page 27 Aug 6, 2013

28 DDR4 BGA Interposer Side View with Riser Riser, Interposer, and DRAM stack up: DRAM Interposer Riser or optional socket PC Board Page 28

29 Probing Techniques: U4154B State Mode > 2.5Gb/s Considerations for designing mid-bus probing SW configurations are different for < > 2.5Gb/s Because trigger sequencer operates up to 2.5GHz Below 2.5Gb/s clock U4154B using both edges of CK0 Above 2.5Gb/s clock U4154B using one edge of CK0 Dual sample mode used for DQ Rising edge and falling edge samples Double probing of DQ signals used for simultaneous R/W data capture with independent thresholds For > 2.5Gb/s - Use Rising and Falling Read / Write Data labels in waveform Decoder re-assembles Rising and Falling samples Above 2.5Gb/s State mode capture of CK0, CK1, and DQS don t toggle They are only sampled once on each clock cycle. Timing Zoom and DDR eye scan used to view CK0, CK1, and DQS Page 29

30 Probing Techniques: U4154B State Mode > 2.5Gb/s Considerations for designing mid-bus probing continued Run simulations on entire system with and without probing. Ensure loading on system will be tolerated Ensure adequate eye for logic analyzer data valid window (minimum 100ps x 100mV for Keysight U4154B) Ensure signal routing meets logic analyzer requirements Clock routed to clock input Clock qualifier (CKE) routing into clock qualifier inputs Route RESET to clock input on Pod 7 of clocking module as clock qualifier Page 30

31 Probing Techniques: U4154B State Mode > 2.5Gb/s Considerations for designing mid-bus probing continued Use Keysight DDR Config Creator Tool to simplify and ensure: Proper labels for SW tools, DDR triggers and DDR setup assistant Proper scan windows for State mode Provides scan triggers for State mode setting sample positions Page 31

32 Probing Techniques: U4154B State Mode > 2.5Gb/s Mid-Bus Routing Recommendations Placing the Soft Touch connectors close to the DRAM generally provides better eyes than mid-bus: Drivers in the DRAM are typically weaker than the Memory controller drivers Location near the DRAM minimizes reflections Ideal locations would be ADD/CMD/DQ Write at DRAM and DQ Read at memory controller Use flow-through routing whenever possible. Keep stubs from inner trace layers to pads (using vias) to a minimum in number and length. Stubs increase loading and reflections resulting in degraded eyes. Distance between buried Tip R and mid-bus probe will act as a low pass filter and degrade the bandwidth of signals into the logic analyzer. Page 32

33 Agenda Overview Benefits and challenges for DDR4 and LPDDR4 >2400Mb/s Breakthrough Insight Gained from Logic Analyzer Techniques to address debug and validation challenges DDR Eye Scan insight DDR4 >3.1 Gb/s DIMM system - Tuning tool - Waveforms and Burst Trigger - View Initialization - Follow the initialization signal flow - Compliance and Performance Tools Successful logic analyzer probing techniques for higher data rates DDR Solution Overview, Recommendations, Q&A Page 33

34 Comprehensive DDR4 / LPDDR4 Insight with U4154B Connect Acquire View & Analyze DIMM / SODIMM Interposers Capture highest data rates! 4 Gb/s BGA interposers Mid-Bus & specialty Probing Capture smallest eyes! 100mV x 100ps at probe point. Sequential Triggers up to 2.5GHz or 4Gb/s! 12.5GHz Timing Zoom 256k deep Up to 200M deep traces Waveforms Listing with Decoders DDR Protocol Compliance Performance Analysis Bus Level Signal Integrity Insight Page 34

35 Solutions to succeed for DDR4 and LPDDR4 Broad coverage for DDR4 and LPDDR4 design and test solutions Physical Layer Simulation with DDR4 specific tools Physical Layer Compliance Test Measurements and Debug Functional Compliance Test Measurements and Debug Physical Layer Signal Injection U4154B system MSOX9130A Infiniium Series scope with N6462A DDR4 Compliance Software Page 35

36 Breakthrough Digital and Analog Signal Display MSO mixed signal oscilloscope One instrument with time correlated digital and analog view. Best separation of Read/Write eyes for parametric measurements. Simultaneous capture of 16 ADD/CMD and 4 DQS/DQ Page 36

37 Logic Analyzer and MSO Complementary solutions used to debug faster Features Logic Analyzer MSO Simultaneous View of Digital and Analog signals Functional validation Eye diagram display Requires an external scope, via View Scope for up to 4 analog Complete View all ADD/CMD/DQ/DQS Functional Compliance Tests Address/command/control and data validation Qualitative bus level signal integrity insight Simultaneous eye diagram displays to view all signals relative to each other. No measurement on eye One box solution with cross trigger and tight correlation. 16 ADD/CMD digital 4 DQS/DQ Analog Partial view 16 command and address (depending on number of digital channels connected). Quantitative measurements Parametric Compliance Tests Eye height and eye width measurements Page 37

38 Recommendations: Join JEDEC and download DDR4 and/or LPDDR4 Specifications for your design Follow design guidelines from chip vendors Simulate your system with and without probing Perform physical layer compliance tests with scope Perform functional layer compliance tests with logic analyzer Use both scope and logic analyzer for debug and test Page 38 MemCon Aug 6, 2013

39 Contact Keysight For more information on Keysight Technologies products, applications or services, please contact your local Keysight office. The complete list is available at: Product Selection and Configuration Assistance, Education and Training US phone: Press # then 2 Hours: 8:00am 8:00pm ET, Mon - Fri Page 39 Aug 6, 2013

40 U4154A/B DDR4 <2.5Gb/s Configuration Two U4154A/B logic analyzer modules M9502A 2 slot AXIe chassis User-supplied Host PC PCI Express Cable and adapter FS2510 DDR4 DIMM interposer with seamless cable connections to U4154A/B DDR4 System under test Logic Analyzer System SW common to: U4154A/B series series PCI Express Gen3 HDMI Page 40