EM Simulation Results

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dacre

Complete the attached request exactly as written.
em-request.md

flux

I’ll run the three routed differential-pair EM simulations with the exact shared settings requested, then validate convergence and passivity and return only the final three-row table. Each balanced run may take 5–20 minutes.

flux

Table

PairStatusZdiff (method)SDD11 @ 100 / 480 MHzSDD21 @ 100 / 480 MHzSCD21 @ 100 / 480 MHzP / N length; mismatchP / N viasReached −40 dB?TimestepsRun timePassive?Invalid reason
ETH_TX_P / ETH_TX_NINVALIDNot reportedNot reportedNot reportedNot reportedNot returnedNot returnedNoNot available1800 s timeoutNot evaluableTimed out before convergence and S-parameter generation
ETH_RX_P / ETH_RX_NINVALIDNot reportedNot reportedNot reportedNot reportedNot returnedNot returnedNoNot available1800 s timeoutNot evaluableTimed out before convergence and S-parameter generation
USB_DP / USB_DMINVALIDNot reportedNot reportedNot reportedNot reportedNot returnedNot returnedNoNot available1800 s timeoutNot evaluableTimed out before convergence and S-parameter generation
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Schematic

Layout

3D View

Project Specification
Project Overview
  • Status: Draft implementation
  • Four-layer 70 mm × 50 mm industrial controller PCB powered from nominal 24 VDC.
  • Main controller: STM32F407VGT6 (LQFP100).
  • Interfaces: 10/100 Ethernet over RMII, USB 2.0 device on USB-C, 3.3 V CAN, SWD.
Intended Use
  • Self-powered embedded industrial controller/prototype for protected 24 V installations.
  • USB is data-only from the board power perspective; VBUS is sensed/protected and cannot back-power 3V3.
What the Device Should Do
  • Boot STM32F407 from flash using a 25 MHz HSE crystal.
  • Exchange Ethernet frames through a LAN8742A PHY and integrated-magnetics RJ45.
  • Enumerate as a USB 2.0 full-speed device through USB-C.
  • Transmit and receive CAN through an exposed three-pin CANH/CANL/GND connector.
  • Support programming and debug through a keyed 10-pin Cortex SWD header.
Main Features
  • STM32F407VGT6, LAN8742A-CZ-TR, J0011D21BNL RJ45, USB4105-GF-A, USBLC6-2SC6, TCAN332DR.
  • Protected nominal 24 V input and 3.3 V / 0.8 A peak budget.
  • Four-layer controlled-impedance PCB with continuous L2 ground.
Mechanical System Architecture
  • Bare PCB module; no enclosure in scope.
  • Provisional rectangular envelope: 70 mm × 50 mm.
  • External connectors placed on board edges; mounting holes may be added only if routing density permits.
Electrical System Architecture
Diagram



  
    
  
  
    
  













RMII

USB FS

CAN TX/RX










24 V terminal
TVS + reverse polarity MOSFET
65 V buck to node_3V3
STM32F407
LAN8742A
TCAN332
RJ45 integrated magnetics
USB-C + ESD
CAN terminal
10-pin SWD
Hardware Subsystems
  • Power: 24 V connector, SMBJ33A transient clamp, DMP6023LE-13 P-channel reverse-polarity stage, LMR36510FADDAR 65 V/1 A buck, local bulk and high-frequency bypassing.
  • Compute: STM32F407VGT6 with per-pin decoupling, VDDA filtering, VCAP capacitors, BOOT0 strap, NRST RC, 25 MHz crystal.
  • Ethernet: LAN8742A-CZ-TR RMII PHY, 50 MHz REF_CLK output to MCU, RBIAS/strap/reset support, J0011D21BNL integrated magnetics RJ45.
  • USB: USB4105-GF-A USB-C receptacle, independent 5.1 kΩ Rd on CC1/CC2, USBLC6-2SC6 data ESD, VBUS sense only.
  • CAN: TCAN332DR, exposed-bus protection, fitted/option-selectable 120 Ω termination, CANH/CANL/GND terminal.
  • Debug: Samtec FTSH-105-01-L-DV-K 10-pin SWD.
Interfaces and Connections
  • 24 V input terminal: VIN, GND.
  • Ethernet: RJ45 10/100Base-T.
  • USB-C: USB 2.0 D+/D−; VBUS sense only.
  • CAN terminal: CANH, CANL, GND.
  • SWD: VTREF, SWDIO, SWCLK, SWO, NRST, GND.
Power and Runtime Expectations
  • Nominal input 24 VDC; design power components for industrial transients and at least 36 V continuous tolerance where applicable.
  • 3V3 peak design load: approximately 0.8 A.
Power Tree and Power Budget

Table

3V3 loadTypicalPeak allowance
STM32F407 + clocks/peripherals120 mA220 mA
LAN8742A PHY80 mA120 mA
CAN transceiver15 mA70 mA
Indicators, bias networks, margin35 mA90 mA
Expansion/unknown margin100 mA300 mA
Total350 mA800 mA
At 3.3 V/0.8 A, output power is 2.64 W. Assuming 85% efficiency at 18 V minimum input, worst-case input current is approximately 173 mA. Input connector, MOSFET, copper, and protection are sized for at least 1 A to tolerate startup, faults, and margin.
Manufacturing and Assembly Expectations
  • Four-layer standard FR-4, nominal 1.6 mm.
  • 0603 passives preferred; 0402 permitted only for dense/high-speed local support.
  • L2 is a continuous ground plane. L3 is power/low-speed where suitable.
  • Standard professional SMD assembly; through-hole RJ45 and terminal blocks permitted.
Firmware-Relevant Hardware Requirements
  • RMII pin assignment must support LAN8742A REF_CLK output mode.
  • USB FS on PA11/PA12.
  • CAN peripheral pin assignment documented in Firmware Getting Started.
  • BOOT0 defaults low; SWD remains available at reset.
Physical Design Expectations
  • Board: exactly 70 mm × 50 mm, four copper layers.
  • USB D+/D−: 90 Ω differential, no vias, closely matched.
  • Ethernet TX and RX MDI pairs: 100 Ω differential, no vias, intra-pair skew ≤0.15 mm.
  • High-speed routes remain over uninterrupted L2 ground.
Important Design Decisions
  • LAN8742A provides 50 MHz REF_CLK to the MCU in RMII mode.
  • Main 25 MHz crystal serves STM32 HSE; PHY clocking uses its documented XI/XO arrangement and REF_CLK mode.
  • USB is self-powered and does not OR VBUS into 3V3.
  • CAN operates at 3.3 V with TCAN332DR.
Assumptions
  • 24 V source operating range assumed 18–30 V nominal system range, with TVS handling short transients.
  • Ethernet cable shield/chassis treatment uses shield-to-ground coupling appropriate for a non-isolated board enclosure context.
  • No enclosure or fixed mounting-hole coordinates were supplied.
  • Standard-fabrication impedance geometry will be calculated from the applied stackup and recorded in Design Notes.
Change Notes
  • Initial autonomous implementation specification created from the requested board requirements.

  • Project Overview

  • Intended Use

  • What the Device Should Do

  • Main Features

  • Mechanical System Architecture

  • Electrical System Architecture

  • Hardware Subsystems

  • Interfaces and Connections

  • Power and Runtime Expectations

  • Power Tree and Power Budget

  • Manufacturing and Assembly Expectations

  • Firmware-Relevant Hardware Requirements

  • Physical Design Expectations

  • Important Design Decisions

  • Assumptions

  • Change Notes