AN 835: PAM4 Signaling Fundamentals

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ID 683852
Date 3/12/2019
Public
Document Table of Contents
Document Table of Contents x
1. Introduction 2. CEI-56G-MR Transmitter 3. CEI-56G-MR-PAM4 Interface Details 4. CEI-56G-MR-PAM4 Receiver 5. PAM4 Link Case Study 6. Medium Reach (MR) PAM4 System Design Study 7. Glossary and Acronyms 8. References 9. Document Revision History for AN 835: PAM4 Signaling Fundamentals
1. Introduction x
1.1. NRZ Fundamentals 1.2. Standards Using PAM4 Coding Scheme 1.3. CEI-56G Interconnect Reaches and Application Distances
1.3. CEI-56G Interconnect Reaches and Application Distances x
1.3.1. VSR (Very Short Reach) Chip-to-Module 1.3.2. MR (Mid-Range Reach) - Chip to Chip Within a PCBA 1.3.3. LR (Long Reach) - Chip to Chip Across a Backplane/Midplane or a Cable
2. CEI-56G-MR Transmitter x
2.1. Naming Conventions 2.2. Eye Height (EH6) and Eye Width (EW6) 2.3. Eye Linearity 2.4. Electrical Characteristics 2.5. PAM4 Jitter Methodology 2.6. TX Pre-Emphasis Method
2.4. Electrical Characteristics x
2.4.1. Transmitter Characteristics 2.4.2. Transmitter Return Loss 2.4.3. Transmitter Linearity (RLM) 2.4.4. Signal-to-Noise-and-Distortion Ratio (SNDR)
3. CEI-56G-MR-PAM4 Interface Details x
3.1. COM Introduction 3.2. Normative Channel Specification COM 3.3. Informative Channel Insertion Loss 3.4. Informative Channel Return Loss
3.1. COM Introduction x
3.1.1. Backplane Measurements
4. CEI-56G-MR-PAM4 Receiver x
4.1. Challenges in Analyzing PAM4 Signals 4.2. PAM4 Receiver Architecture 4.3. Equalization Technique 4.4. CEI-56G-MR-PAM4 Receiver Details
4.2. PAM4 Receiver Architecture x
4.2.1. Analog vs. Digital Receiver 4.2.2. Slicer 4.2.3. Clock and Data Recovery (CDR)
4.4. CEI-56G-MR-PAM4 Receiver Details x
4.4.1. Electrical Characteristics 4.4.2. Receiver Input Return Loss 4.4.3. Receiver Interference Tolerance 4.4.4. Receiver Jitter Tolerance
5. PAM4 Link Case Study x
5.1. OIF_Stressed 5.2. OIF_Compliant
5.1. OIF_Stressed x
5.1.1. Channel Characteristics 5.1.2. OIF_Stressed PAM4 Link Simulation with the Advanced Link Analyzer
5.2. OIF_Compliant x
5.2.1. Channel Characteristics 5.2.2. OIF_Compliant PAM4 Link Simulation with the Advanced Link Analyzer
6. Medium Reach (MR) PAM4 System Design Study x
6.1. System Power 6.2. System Cost 6.3. Board Space 6.4. Conclusion
1. Introduction
2. CEI-56G-MR Transmitter
3. CEI-56G-MR-PAM4 Interface Details
4. CEI-56G-MR-PAM4 Receiver
5. PAM4 Link Case Study
6. Medium Reach (MR) PAM4 System Design Study
7. Glossary and Acronyms
8. References
9. Document Revision History for AN 835: PAM4 Signaling Fundamentals

2.4.1. Transmitter Characteristics

The following table defines the basic transmitter characteristics for an OIF-CEI56G-MR interface.

Table 5.  Transmitter Electrical Output Specifications
Characteristic Symbol Condition MIN. TYP. MAX. UNIT
Baud Rate T_Baud   18.0   29.0 Gsym/s
Output Differential Voltage T_Vdiff See 1, 2     1200 mVppd
DC Common Mode Voltage T_Vcm See 3 0   1.9 V
Output AC Common Mode Voltage T_VcmAC See 4, 5     30 mVrms
Single-Ended Transmitter Output Voltage T_Vse See 6, 7 -0.3   1.9 V
Differential Output Return Loss T_SDD22 8       dB
Common Mode Output Return Loss T_SCC22 9       dB
Level Separation Mismatch Ratio T_RLM See10 11 12 0.95     %
Steady-State Voltage T_Vf 0.4   0.6 V
Linear Fit Pulse Peak T_Pk 0.80 x T_Vf     V
Signal-to-Noise-and-Distortion-Ratio T_SNDR 31     dB
1 Signals are specified as measured through a fourth-order Bessel-Thomson low-pass response with 40 GHz 3 dB bandwidth.
2 Measured as described in Section 17.3.1.2.
3 Measured as described in Section 17.3.1.2. of the CEI-56G-MR-PAM4 Medium Reach Interface, OIF2014.245.04
4 Signals are specified as measured through a fourth-order Bessel-Thomson low-pass response with 40 GHz 3 dB bandwidth.
5 Measured as described in Section 17.3.1.2 of the CEI-56G-MR-PAM4 Medium Reach Interface, OIF2014.245.04.
6 Signals are specified as measured through a fourth-order Bessel-Thomson low-pass response with 40 GHz 3 dB bandwidth.
7 Measured as described in Section 17.3.1.2 of the CEI-56G-MR-PAM4 Medium Reach Interface, OIF2014.245.04.
8 See Equation 17-4 of the CEI-56G-MR-PAM4 Medium Reach Interface, OIF2014.245.04
9 See Equation 17-5 of the CEI-56G-MR-PAM4 Medium Reach Interface, OIF2014.245.04
10 Signals are specified as measured through a fourth-order Bessel-Thomson low-pass response with 40 GHz 3 dB bandwidth.
11 Measured as described in Section 17.3.1.2 of the CEI-56G-MR-PAM4 Medium Reach Interface, OIF2014.245.04.
12 Measured as described in Section 17.3.1.6 of the CEI-56G-MR-PAM4 Medium Reach Interface, OIF2014.245.04.
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