How to Analyze HDMI PCB Layout

Jaehoon

Introduction

This document shows how to analyze HDMI (High-Definition Multimedia Interface) PCB layout design with PollEx SI (Signal Integrity) tool.

Background: HDMI Specification Version 1.3

• HDMI system architecture
  • The HDMI cable and connectors carry 4 differential pairs; 3 TMDS data and 1 clock channels (TMDS: Transition Minimized Differential Signaling).

Fig. 1. HDMI Block Diagram.

• • Maximum data rate (from Wikipedia) <- Used as one SI analysis condition
    • Max. TMDS clock= 340 MHz for 1920*1080 at 120 Hz or 2560*1440 at 60 Hz
    • Max. bit rate for 3 TMDS data channels= 10.2 Gbit/S
    • Max. bit rate for each TMDS data channel= 3.4 Gbit/S (1.7 GHz = Time period 0.588 nS)

• Electric specifications
  • One TMDS differential pair: Current driver at Transmitter (Tx), Pull up resistor at Receiver (Rx)

 

Fig. 2. Conceptual schematic for one TMDS differential pair.

 

Table 1. Required operation conditions for HDMI Interface. 

• • TMDS source requirements: Testing Point (TP1) on Board (PCB), Pattern = Layout design

Fig. 3. Balanced source test load.

 

Fig. 4. Eye diagram mask at TP1 for Source requirements.

 

Analysis: HDMI Layout Design with PollEx SI

• Open HDMI PCB design file
  1. PollEx PCB > File > Altair_PCB_HDMI_sample.pdbb
  2. Save AS Project

• Explore HDMI Layout (Pattern)

1. 1. Tool > PCB Explorer > Net > CN-||MCU_HDMI_TX0P||SIGN.. ~ CN-||MCU_HDMI_TXCP||SIG...> Excl

 

Fig. 5. HDMI TMDS Layout Design (Exclusive View).

                2.  Option > Net 2D/3D Viewer : Tx= U1 (IC-NXP4330), Rx= CN1 (47151-0001)

Fig. 6. HDMI TMDS Layout Design (Net 2D View).

• Include “IBIS model” for IC-NXP4330 and “Linear model” for 47151-0001
  1. Properties > Parts > Double-click “IC-NXP4330” > Device Model Files > Add “NXP3330_HDMI.ibs” > Click “Display” to open IBIS Manager > hdmi_minimp_33_0000

Fig. 7. HDMI IBIS model for TDMS transmitter (NXP4330).

                2.  Properties > Parts > Double-click “47151-0001” > Device Model Files > Add “Connector_linear.dmf” > Click “Display” to open Linear Device Modeler > PU50_TO33

• • • Vcc = 3.3 V & Rin_p= 50 Ohm with reference to Fig. 2 and Table 1

(a) Model Spec

(b) Model Data

Fig. 8. Linear model for HDMI receiver (connector).

 

• Execute “SI analysis: Net Topology Analyzer” for one TMDS differential pair design
  1. Analysis > Net Topology Analysis > Select Net for Analysis > Select “CN-||MCU_HDMI_TX0N||SIGN00250” and “CN-||MCU_HDMI_TX0P||SIGN00249” > Click “Analyze”

Fig. 9. Net topology for one HDMI TMDS layout

                 2.  Analysis > Net Analysis:

• • • Active Driver Pin = U1_B24
    • Pulse Period= 0.588 (nS) from the condition that “Max. bit rate for each TMDS data channel= 3.4 Gbit/S (1.7 GHz= Time period 0.588 nS)”
    • Device Models: Input = PU50_TO33 & Output = hdmi_minimp_33_0000

 

(a) Overall setting

 

(b) Device Model setting

Fig. 10. Setting for Topology Network Analysis.

                3.  Check the final simulation results: Eye diagram

• • • Waveform: CN1_7 & CN1_9 - Vdiff
    • Eye Mask setting with reference to Fig. 4: Height (V) = 0.5 (=0.25+0.25), Top/Bottom= 37 (=(0.68333-0.31666)*100), Middle width(%)= 70 (=(0.85-0.15)*100), Reference voltage = Ground

 Fig. 11. Eye diagram (green) at HDMI connector with Eye mask (red).

References

• High-Definition Multimedia Interface - Specification Version 1.3, June 22, 2006.
• HDMI from Wikipedia, https://en.wikipedia.org/wiki/HDMI

 

Attachment: Solved PollEx SI Project.