How to Analyze USB PCB Layout with PollEx SI

1. Introduction

This document shows how to analyze USB (Universal Serial Bus) PCB layout design with PollEx SI (Signal Integrity) tool.

2. Background: USB Specification Revision 2.0

Figure 1. USB Cable


Figure 2. Measurement Planes.

Figure 3. Transmitter/Receive Test Fixture for TP2.


Figure 4. Transmit waveform requirements (Eye Mask) for a hub measured at TP2.


Table 1. Eye Mask Values for Figure 4. 

3. SI Analysis: USB PCB Layout Design with PollEx

Figure 5. USB D+/D- Layout Design (Exclusive View).

Figure 6. USB Layout Design (Net 2D View).

    1. Properties > Parts > Double-click “IC-NXP4330” > Device Model Files > Add “NXP3330_USB.ibs” > Click “Display” to open IBIS Manager > USB20_HS

Figure 7. USB IBIS model for USB transmitter (NXP4330). 

             2. Properties > Parts > Double-click “675031020” > Device Model Files > Add “USB_Connector_linear.dmf” > Click                         “Display” to open Linear Device Modeler > USB_PD45

(a) Model Spec

(b) Model Data

Figure 8. Linear model for USB receiver (connector).

    1. Analysis > Net Topology Analysis > Select Net for Analysis > Select “MCU_HOST_USB+” and “MCU_HOST_USB-” > Click “Analyze”

Figure 9. Net topology for USB differential pair layout

2. Analysis > Net Analysis in Net Topology Analyzer

(a) Overall setting

(b) Device Model setting

Figure 10. Setting for Topology Network Analysis.


                  3. Check the final simulation results: Eye diagram


Figure 11. Eye diagram (green) at USB connector with Eye mask (red).