POF Knowledge Development EMC Lessons Learnt on Gigabit Ethernet - PowerPoint PPT Presentation

POF Knowledge Development EMC Lessons Learnt on Gigabit Ethernet Implementation for ADAS & AV Rubén Pérez-Aranda (rubenpda@kdpof.com) AESIN CONFERENCE | 2 nd Oct 2018

POF KDPOF in a nutshell Knowledge Development • Fabless silicon vendor • KDPOF develops state of the art semiconductors for optical communications of 100 Mbps, 
 1 Gbps, and nGbps for Automotive applications, among others • Incorporated in 2010. ~30 workers, most of them Engineers • Located in Tres Cantos, Madrid, Spain • ISO 9001:2015 • Standardized technology: IEEE Std 802.3bv “Physical Layer Specifications and Management Parameters for 1000 Mb/s Operation Over Plastic Optical Fiber” • KDPOF supplies Ethernet PHY chipset for many automotive applications: HV batteries, BMS, EV, safe backbone, smart antenna modules, infotainment, ADAS, AV • The key: POF cable harness provides galvanic isolation and is free of EMC problems • Currently, Tier-1s and OEMs are implementing ECUs with KDPOF chipset for 1 Gbps and 100 Mbps � 2 AESIN CONFERENCE | 2 nd Oct 2018

POF Why EMC topic? Knowledge Development • ADAS & AV are emerging, demanding to communications networks: • Higher speeds (e.g. ≥ 1 Gbps) • Lower latencies (e.g. < 100 us) • Ethernet is being positioned to be the communications technology to make the fusion of sensors, actuators and AI computing units • Faster speeds make more di ffi cult to meet the EMC constraints: • Wider electromagnetic spectrum needs to be used • Systems become less immune to radiated and conducted noise • Systems emit noise in higher frequencies with higher power • OK … but POF is optical, … why EMC? • EMC specifications highly impact in: • The Ethernet PHY IC design: clock strategy, data interfaces, etc. • The integration of the IC at ECU level: schematic, PDN, SI, layout, etc. • The components selection: clock reference, power management, filters, decoupling, etc. • We will see the process to make a Gigabit Ethernet PHY EMC compliant and the lessons learnt � 3 AESIN CONFERENCE | 2 nd Oct 2018

POF The target: GEPOF Ethernet PHY Knowledge Development 1000BASE-RHC PHY compliant with IEEE Std 802.3bv Transceiver IC ( KD1053 ): ‣ PCS and PMA sublayers Optical header connector: ‣ Modulation, FEC, channel equalization, 
 ‣ PMD sublayer + MDI timing recovery, Ethernet frames en/decoding ‣ TX: driver IC ( KD9101 ) + LED IC ‣ MAC layer I/F: RGMII, SGMII, etc ‣ RX: TIA IC ( KD9201 ) + Photodiode IC ‣ Mixed-Signal IC: DAC, ADC, PLLs, DSP ‣ Optical lenses for light coupling ‣ Safety sensors: voltage, temperature, … ‣ Mechanical attachment, mating ‣ Management: MDIO ‣ EMC shielding (PMD RX handles μ A) ‣ PTP , SyncE, … � 4 AESIN CONFERENCE | 2 nd Oct 2018

POF The reference design Knowledge Development Objectives : SFP I/F ‣ To be a guide for Tier 1 of how to integrate the PHY in an ECU (SGMII, 1000Base-X) ‣ To solve components selection (clocks, PMIC, Cs, Rs, Ls, filters) ‣ To solve power distribution networks (decoupling, filtering, stability) ‣ To solve signal integrity PS filters and ‣ To recommend PCB stack-up and layout protections ‣ To demonstrate full functionality (e.g. WU/Sleep) PHY ‣ To be a technology evaluation vehicle Power ‣ To operate in temperature range: -40º — +105 ºC management ‣ To support car battery supply conditions SyncE ‣ To be EMC compliant w/o metal box Battery Configuration Wake-up & Sleep Management I/F Indicators � 5 AESIN CONFERENCE | 2 nd Oct 2018

POF Noise emissions compliance (EMI) Knowledge Development RE. In front of the EUT RE. In front of the harness 1 GHz < f < 6 GHz 200 MHz < f < 1000 MHz 30 MHz < f < 200 MHz Horn antenna. V/H. 3 positions. Logo-periodic antenna. V/H. Biconic antenna. V/H. RE. In front of the harness CE. Current method CE. Voltage method 0.15 MHz < f < 30 MHz 0.15 MHz < f < 320 MHz 0.15 < f < 108 MHz Monopole antenna Current clamp LISN (AN) � 6 AESIN CONFERENCE | 2 nd Oct 2018

POF Noise immunity compliance (EMS) Knowledge Development RI, RF. In front of the EUT RI, RF. In front the harness RI, BCI 1 GHz < f < 6 GHz. CW, PM217 200 MHz < f < 1 GHz. CW, AM, PM18 0.1 MHz < f < 400 MHz. CW, AM Horn antenna. V/H. 3 positions. Logo-periodic antenna. V/H. Current clamp. Several positions, wires configurations. RI, Radar pulse. In front the EUT RI, Handy transmitters 1.2 — 1.4 GHz. 2.7 — 3.1 GHz. PM300 26 MHz < f < 6000 MHz, CW, AM, PM18, PM217, PM300 Horn antenna. V/H. 3 positions. Different antennas � 7 AESIN CONFERENCE | 2 nd Oct 2018

POF Lesson 1: standards vs. OEM’s specs Knowledge Development • Just an example, CISPR 25:2016, radiated emissions between 1 and 3 GHz, component level • CISPR 25 specifies test and calibration methods, but only give recommendations on the limits • OEMs norms are usually derived from international standards, with amendments • If we combine w/c limit of several OEMs (Volvo, JLR, MBN, BMW, Ford), we have a much harder spec to meet � 8 AESIN CONFERENCE | 2 nd Oct 2018

POF Lesson 2: the EMC qualification process Knowledge Development Redesign M <<< N M cycles N cycles EMC EMC Compliance Qualified EMC Pre- compliance = COST 1 × EMC 1 × EMC pre-compliance compliance session laboratory � 9 AESIN CONFERENCE | 2 nd Oct 2018

POF EMC pre-compliance: radiated emissions Knowledge Development VBAT TEM cell LISN PSU w/ FLT GND LISN SA LNA 40dB DC-block Port 1 Port 2 50 Ω load EUT POF PORT RF shielding box • pre-RE: • Near-field E/H aligned with TEM cell • Far-field results can be correlated if radiative structures do not change (di ff erential analysis) • Very useful to debug PDN, SS, decoupling, layout, and noise emissions root causes • High repeatability! � 10 AESIN CONFERENCE | 2 nd Oct 2018

POF EMC pre-compliance: conducted emissions Knowledge Development VBAT TEM cell LISN PSU w/ FLT LISN GND EUT POF PORT SA RF Splitter RF shielding box • pre-CE CM: • 0º resistive splitter • It correlates with far-field RE below 1 GHz in front of the harness • It correlates with current method CE < 320 MHz • pre-CE DM: • Inductive 180º splitter • Used together with pre-CE CM to correlate voltage method and current method CE results � 11 AESIN CONFERENCE | 2 nd Oct 2018

POF EMC pre-compliance: radiated immunity Knowledge Development RF-Switch RF-HPA (for PM) PSU Opt. Att. RF-HPAs PSU DM/CM filters Pulses RF Shield SA monitor Generator with TEM CELL inside Eth. tester RF Generator connection MDIO link Golden margin monitor for sensitivity PSU (golden, DUT) � 12 AESIN CONFERENCE | 2 nd Oct 2018

POF Lesson 3: Power supply (CM & DM) filters Knowledge Development pre-CE CM: RGMII baseline pre-CE CM: RGMII, PS filter � 13 AESIN CONFERENCE | 2 nd Oct 2018

POF Lesson 4: PM IC spread-spectrum Knowledge Development PM IC simulation predicts noise reduction pre-CE CM: RGMII baseline pre-CE CM: RGMII, PS filter, PM IC SS � 14 AESIN CONFERENCE | 2 nd Oct 2018

POF Lesson 5: DSP and RGMII spread-spectrum Knowledge Development • KD1053 IC clock architecture was designed from the beginning taking into consideration EMC performance • 5 PLLs within the IC: • Clean low jitter clocks: 1 × PLL for DAC + 1 × PLL for ADC • Spread-spectrum modulated clocks: 1 × PLL for DSP TX, 1 × PLL for DSP RX, 1 × PLL for xMII I/F TX pre-CE CM: RGMII baseline pre-CE CM: RGMII, PS filter, PM IC SS, DSP SS, I/F SS 17 dB @ 500 MHz 31dB @ 125 MHz � 15 AESIN CONFERENCE | 2 nd Oct 2018

POF Lesson 6: SGMII interface Knowledge Development • Data I/F based on SerDes may present additional advantages in EMC: • Di ff erential matched transmission lines vs. single-ended unmatched signals of RGMII • Embedded clock vs. source synchronous transmission with 125 MHz clock of RGMII • Reduced number of traces: 2 × TX + 2 × RX traces vs. 6 + 6 of RGMII pre-CE CM: RGMII baseline pre-CE CM: SGMII, PS filter, PM IC SS, DSP SS, I/F SS � 16 AESIN CONFERENCE | 2 nd Oct 2018

POF Lesson 7: Spread spectrum is very important in high frequency Knowledge Development • pre-RE TEM cell measurements show noise cleaning produced by clock SS in DSP and RGMII interface • As higher the harmonic is, the e ff ect of SS is more important • Highlighted the reduction by SS for some RGMII harmonics pre-RE: RGMII baseline pre-RE: RGMII, PM IC SS, DSP SS, I/F SS -18dB -14dB -13dB -15dB -16dB -16dB Sinc response due to RGMII random data � 17 AESIN CONFERENCE | 2 nd Oct 2018

POF Lesson 8: 25 MHz XTAL vs. Oscillator Knowledge Development • 25 MHz clock reference. Should we use XTAL or OSC? — No easy response from EMC viewpoint • XTAL: better noise emissions performance, cheaper, but it may be worse in immunity • OSC: more robust against noise, but you can measure energy in harmonic +100, because very short t r /t f • … and MEMS based OSC? — Controlled tr/tf, lower emissions with good immunity. But … worse jitter, which penalizes the sensitivity pre-RE: RGMII, PM IC SS, DSP SS, I/F SS — OSC pre-RE: RGMII, PM IC SS, DSP SS, I/F SS — XTAL � 18 AESIN CONFERENCE | 2 nd Oct 2018