SnpExpert – S-parameter Exploration

Background

S-parameters, traditionally used in RF/Microwave design, are widely adopted by high speed digital designs as the multi-gigabit interface continues to advance to higher data rate. Xpeedic SnpExpert provides a quick way to understand the electrical characteristics of the passive interconnectors in a system by not only viewing the S-parameter in frequency domain but also examining the time domain reflectometry (TDR) .One-click definition of differential pairs and victim/aggressor setup, together with the built-in NEXT, FEXT, PSXT, ILD, ICR, and ICN, allows user to quickly evaluate the crosstalk. The built-in delay and skew calculator requires no cumbersome circuit schematic setup. The built-in compliance metrics with IEEE 802.3ap, 802.3ba, 802.3bj and OIF CEI 25G/28G standards quickly reveal the S-parameter compliance. The built-in passivity, causality, reciprocity, and stability metrics tell the quality of the S-parameter. The built-in template automates the process from S-parameter plotting to report in Word or PPT. The through-only de-embedding method helps SI engineers to quickly obtain the DUT characteristics by removing the fixture effect. The 2D RLCG full-wave solver enables quick and accurate transmission line characterization.

FEATURES

Easy S-parameter and TDR Plot

  • Provides several ways to easy plot frequency domain S-parameter and TDR.

Easy Diff-Pair Setup and Processing

  • SnpExpert provides easy ways to setup the differential pairs and rich functions for post-processing.

Grid Plot

  • SnpExpert allows users to grid plot diff-pair S-parameter and TDR in both single-ended and differential modes similar to PLTS.

Powerful Crosstalk Analysis

Crosstalk analysis flow is quite helpful for user to evaluate the crosstalk effect after setup victim and aggressor:

  • Crosstalk between single-ended port
  • Crosstalk between differential pairs
  • Crosstalk between single-ended port and differential pair

SnpExpert has built-in crosstalk plots including FEXT, NEXT, PSXT, ILD, ICN, ICR, IL_fitted, ILD_rms and ICR_fit.

Compliance Metrics

  • Built-in Compliance metrics: IEEE 802.3ap, IEEE 802.3ba and, IEEE 802.3bj, OIF CEI-25G/28G, SAS 3.0, PCIe 3.0, SATA 3.2 and so on.

Quality Metrics

  • SnpExpert has built-in algorithm to evaluate S-parameter quality metrics and fix quality issues based on enforcement algorithm, including passivity, causality, reciprocity and stability.

Delay and Skew Calculator

  • SnpExpert has built-in delay and skew calculator for both single-ended trace and differential pairs.

Built-in template for RFIC

  • SnpExpert has built-in template to show S-parameter, L, Q, M, K and other parameters for various RF components, such as inductor, transformer, filters, balun, diplexer, and coupler.

Powerful De-embedding Method

Support multiple de-embedding methods to meet different application scenario:

  • Open-Short De-embedding to remove the pad parasitic for on-chip applications.
  • Through-Only De -embedding to remove the fixture effect for SI applications, support both symmetric and asymmetric TOD w/ and w/o fixture A or fixture B.
  • Halve S-parameter Matrix to get the s parameter of the 2x through-only fixture.

Accurate Dk/Df Extraction

  • After using Thru-Only De-embedding or Delta-L De-embedding method to remove fixture effect from DUT, Dk/Df extraction method is applicable to extract Dk, Df and even surface roughness. SnpExpert supports several Dk/Df extraction methods, including S3 based method, Delta-L based method and optimization based method. Extracted Dk/Df is quite easy to export for specified frequency points in excel format.

Eye Diagram

  • Plot NRZ and PAM-4 modulation eye diagram based on bit pattern, data rate and rise/fall time setting, also support CTLE, FFE and FIR for both Tx and Rx.

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