Ethernet SFP+ QSFP+ Tx Compliance & Debug Solution

TekExpress SFP-TX user interface for PHY measurements including SFP+ Direct Attach Cable Specifications “10GSFP+CU and QSFP+ specification”.

Features and benefits

Applications

TekExpress SFP-TX measurement setup

The SFP-TX solution helps customers to easily select measurements for SFF-8431 (SFP+ Tx) & SFF-8635 (QSFP+ Tx) testing. Simple and easy-to-use measurement setup helps customers perform all measurements with a single button click. Automation options help customers meet compliance needs and generate detailed reports. User-defined mode lets customers make changes to the test limits and perform margin testing beyond compliance.

DPOJet SFP-TX measurement setup

The SFP-TX solution helps customers to easily select measurements for SFF-8431 (SFP+ Tx) & SFF-8635 (QSFP+ Tx) testing. All masks, limits, and measurement parameters are automatically configured for the customer. Additionally, customers have the flexibility to change selected measurements and measurement configurations within DPOJET. SFP-TX DPOJET options provide a new standard-specific UI.

Seven new additional measurements have been added including VMA, Rise Time, Tx-Qsq, DDPWS, Fall Time, UJ, and TWDPc which were not part of the original DPOJET package. Setup files are provided based on different signal types such as 8180, PRBS9, and PRBS31. Signal-specific setup files allow design engineers to perform measurements on different signal types, letting them go into Analysis and Debug mode.

Simplified instrument setup - Save time and resources

Setup and test execution is simple with the SFP-TX software. The oscilloscope acquisition and analysis are all controlled through the SFP-TX automation solution. The software’s Graphical User Interface (GUI) provides an intuitive workflow for setup and testing.

Margin testing

Design characterization is supported beyond SFF-8431 (SFP+ Tx) & SFF-8635 (QSFP+ Tx) compliance requirements for all measurements. Qualify PHY with flexible control over test configurations such as analysis windows and other parameters. User-defined mode lets customers make changes to the test limits and perform marginal testing beyond compliance.

TWDPc - Transmitter Waveform Distortion Penalty for Copper

SFF-8431 SFP+ suggests that this measurement should be performed on SFP+ Host Transmitter Output Specifications at B for Cu.

Customers who plan to use TWDPc measurements need to purchase Option SFP-WDP. TWDPc is a measure of the deterministic dispersion penalty due to a particular transmitter with reference to the emulated multi-mode fibers and a well-characterized receiver. TWDPc is initially defined to characterize the performance of a transmitter in optical links. The same concept has been extended to quantify channel performance as well, especially in high-speed copper links. SFF-8431 Revision 4.1 Table 33 – Host Transmitter Output Specifications at point B for Cu.

For TWDPc compliance, a simulated cable response is required. The response is modeled as a set of delta functions with specific amplitudes and delays. The copper stressor was created from measurements of commonly available direct attach SFP+ cables with the transmitter response de-convolved. The stressor is shown in the following figure and the values are listed in Table 34 of the SFF-8431 SFP+ specification. The sum of all stressor components is normalized to an approximate value of 1.

TWDPc measurements are supported only on C and D Series real-time oscilloscopes with a sampling rate of 100 GS/s and ≥16 GHz bandwidth due to the following:

• The TWDPc script (of 802.3aq, 10GBASE-LRM) processes a PRBS9 pattern requiring at least 16 samples per unit interval.
• Out of concern for the large installed base of sampling oscilloscopes with a record length of around 4000 samples the requirement for 16 samples per unit interval is relaxed to 7 samples per unit interval.
• The relaxation of the requirement for 16 samples per unit interval to just 7 samples per unit interval causes worst-case 0.24 dB TWDPc pessimism over 30 measurements. For DUTs that already have a high WDP, 0.24 dB can be the difference between a Pass or Fail result.
• With a DPO/DSA/MSO70000C/D/DX/SX Series oscilloscope, a 100 GS/s sampling rate is available. Around 10 samples per UI will be obtained from the hardware.

Tektronix recommends to only run TWDPc measurements on DPO/DSA/MSO70000C/D/DX/SX Series oscilloscopes.

SFP module measurements

SFP-TX supports 10 new measurements for the SFP+ module. These include AC Common Mode Voltage Tolerance, Single-ended Input Voltage Tolerance, Crosstalk Source Rise/Fall Time (20-80%), Crosstalk Source Amplitude (P-P Differential), Output AC Common Mode Voltage (RMS), Total Jitter, Data Dependent Jitter, Data Dependent Pulse Width Shrinkage, Uncorrelated Jitter, and Eye Mask Hit Ratio.

SFP total jitter measurements

SFP-TX allows users to enter BER value of in the range of BER e^–2 to –18, providing them the flexibility to calculate Total Jitter at various BER values.

J2 and J9 (under QSFP+ dropdown menu) measurements have been added as informative measurements to SFP-TX, these measurements are part of other 10G standards like 40GBASE-CR4 and XLPPI.

De-embedding feature

As data rates increase, high-speed serial technologies have introduced new test methodologies and requirements for compliance testing. As technologies such as SFP+ increase in data rates, the eye is closed and different components such as SMA cables can be de-embedded to get better results. SFP-TX provides an option to de-embed the signal using .FLT files.

Report Configuration menu

The Report Configuration menu lets users configure reports, and it provides options such as auto increment and appending.

One-button testing

Once the test bench is set up and the DUT is properly connected, press the Run button to perform the selected test suite. The SFP-TX solution prompts the end-user to put the DUT into different test modes by displaying messages at regular intervals.

Automation support

Save and recall setup files in automation script, with an option to automate the complete test bench. Tektronix end-users can call the SFP-TX application programmatically through NI LabVIEW, NI TestStand™, or any other scripting language for controlling SFP-TX along with other instrumentation such as thermal chambers and power supplies.

Multiple data rate support

Tektronix application supports multiple speeds. Many products available in market support multiple data rates including 9.95328Gbps, 10.3125 Gbps, 10.51875 Gbps and 11.10 Gbps.

Multiple pattern support

Tektronix application supports multiple patterns in user defined mode. Various products available in market support patterns over and above what is specified in SFF-8431 and SFF-8635. User defined mode supports PRBS7, PRBS11, PRBS15,PRBS20 & PRBS23 in addition to patterns supported in Compliance mode including PRBS9, PRBS31 and 8180.

Pass/Fail report

A summary report in .MHT (MHTML) format with Pass/Fail status is automatically generated after tests complete. The report includes test configuration details, waveform plots, and margin analysis to provide more insight into your design.