Fathom-X WiFi Bridge Design

flux

To get it manufactured now, use the exported files like this:
1. Order the bare PCB
Use the Gerber ZIP:
Upload that ZIP to a PCB manufacturer such as JLCPCB, PCBWay, Seeed Fusion, or Elecrow.
Recommended PCB settings:
  • Layers: 4-layer
  • Board size: 30 mm × 120 mm
  • Thickness: 1.6 mm unless you have enclosure constraints
  • Copper: 1 oz
  • Surface finish: ENIG preferred, HASL acceptable
  • Solder mask: any color
  • Impedance control: recommended if your fab supports it, because Ethernet/RMII pairs are present
2. If you want assembly, upload BOM + pick-and-place
For JLCPCB-style assembly, use:

  • BOM — JLCPCB CSV

    CommentDesignatorFootprintJLCPCB Part #LCSC Part #
    GRM31CR72A475KA73LC1
    GRM21BR61E226ME44LC2
    GRM188R61C106MA73DC10, C3C19702
    GRM188R71C104KA01DC11, C15, C17, C18, C19, C20, C6, C8C14663
    GRM1885C1H331JA01DC12
    GRM188R71H104KA93DC13C14663
    C3216X7R2J103K160AAC14
    GRM188R61A475KE15DC16, C5C19666
    GRM188R61A105KA61DC21, C4, C7C15849
    SP4021-01FTG-CD2SOD-323_L1.8-W1.3-LS2.5-RDC720051
    XY301V-A-5.0-2PJ1
    DG250-3.5-02P-11-00A(H)J2
    TYPE-C-2.0-16PIN-SMT-3-ORJ3USB-SMD_TYPE-C16PIN-1C2987387
    PDQ30-Q48-S12-DPS1
    R-78C5.0-1.0PS2
    R-78E3.3-1.0PS4
    RC0603FR-0710KLR1, R10, R11, R2, R3, R4, R9C25804
    RC0603FR-075K1LR5, R6C23186
    RC1206FR-0710RLR7
    RC0603FR-0712K1LR8C22835
    RC0603FR-071K5LR12C22843
    UT11403ST1
    XC6220B331MRU1SOT-23-5
    ESP32-WROOM-32EU2
    LX200V20U4
    LAN8720A-CPU6
    CH340CU7

  • Pick-and-place — JLCPCB CSV

    DesignatorLayerRotationMid XMid Y
    C1Top90-3.2mm-14.5mm
    C2Top0-10.5mm-45.2mm
    C3Top0-3.2mm2.8mm
    C4Top903.2mm4.4mm
    C5Top903.2mm7.6mm
    C6Top0-12.5mm57.2mm
    C7Top0-12.5mm55.4mm
    C8Top0-12.5mm46.9mm
    C10Top04mm31mm
    C11Top04mm18.6mm
    C12Top0-12.4mm23.8mm
    C13Top0-12.4mm28mm
    C14Top0-12.4mm22mm
    C15Top012.775mm17mm
    C16Top012.775mm18.8mm
    C17Top04mm20.8mm
    C18Top04mm22.4mm
    C19Top04mm27.2mm
    C20Top04mm28.8mm
    C21Top012.775mm20.6mm
    D2Top0-12.33mm20mm
    J1Top0-6.5mm-53.4999mm
    J2Top180-8.25mm11.5mm
    J3Top270-9.2mm34.3mm
    PS1Top00mm-31mm
    PS2Top0-5.96mm-5mm
    PS4Top06.84mm-5mm
    R1Top0-12.5mm53.6mm
    R2Top0-12.5mm51.8mm
    R3Top012.5mm49mm
    R4Top012.5mm51mm
    R5Top0-1.2mm35.2mm
    R6Top0-1.2mm33.4mm
    R7Top0-12.4mm26.2mm
    R8Top012.775mm24.3mm
    R9Top0-12.5mm48.55mm
    R10Top0-12.5mm50.2mm
    R11Top012.775mm26.1mm
    R12Top012.775mm27.9mm
    T1Top0-7mm24.9mm
    U1Top00mm6mm
    U2Top00mm49.635mm
    U4Top00mm22mm
    U6Top08.35mm22mm
    U7Top010mm34.2mm
If your manufacturer is not JLCPCB, use the Flux/standard BOM and OpenPNP pick-and-place files instead.
3. Before paying, check these previews
In the fab ordering page:
  1. Open the Gerber viewer.
  2. Confirm the board outline is 30 mm × 120 mm.
  3. Confirm the USB-C connector, tether terminal, and power terminal are at accessible edges.
  4. Confirm there are no obvious missing copper layers.
  5. For assembly, check pick-and-place rotations for:
    • ESP32-WROOM-32E
    • LAN8720A
    • CH340C
    • LX200V20 module/socket
    • UT11403S transformer
    • USB-C connector
    • polarized/special parts if any
4. Important: choose assembly scope carefully
Some parts may not be available through automated JLCPCB assembly, especially:
  • LX200V20
  • UT11403S
  • Possibly the 48V DC/DC converter module
  • Some high-voltage capacitors
Best practical approach:
  • Let the assembler place common SMD parts: resistors, capacitors, ESP32, LAN8720A, CH340C, USB-C, etc.
  • Hand-place or separately source specialty modules/parts: LX200V20, UT11403S, large DC/DC modules if unavailable.
5. After you receive the board
Follow the bring-up plan before connecting the full 48V tether system:
  • First power with current limit.
  • Verify 12V, 5V, 3.3V, and LX200V20 3.3V rails.
  • Program the ESP32 over USB-C.
  • Verify Ethernet PHY detection.
  • Then test tether/HomePlug link.
Do not connect the full tether power source first without current limiting.
kgfairbarn

kgfairbarn

is this a two layer or 4 layer board?

flux

It is a 4-layer board.
Current layout setup:
  • Board size: 30 mm × 120 mm
  • Copper layers: 4
  • Stackup: Standard 4 Layer custom
  • Intended layer use:
    • Top: components + signals
    • Inner layer: ground reference plane
    • Inner layer: power / routing
    • Bottom: signals / routing
A 4-layer stackup is the right choice here because the board has Ethernet/RMII signals, USB, multiple power rails, and a narrow 30 mm form factor.
Export 4-layer files
Check stackup details
Fix package mismatches
Review impedance routing
Assembly guidance
Sign up to send
U2 IO45 - R3 P1
T1 PL_L - J2 1
J3 CC1 - R5 P1
J3 CC1 - R5 P1
J3 CC2 - R6 P1
T1 PL_N - J2 2
U7 V3 - C6 P1
U7 V3 - C6 P1
U7 ~RTS - U2 EN
J3 DP2 - U7 UD+
U7 ~DTR - U2 IO0
U7 ~RTS - U2 EN
J3 DN2 - U7 UD-
J3 CC2 - R6 P1
U2 IO46 - R4 P1
U7 V3 - C6 P1
J3 GND - C7 P2
J3 GND - C7 P2
J3 GND - C7 P2
U3 GND - J3 GND
GND
GND
GND
GND
GND
GND
GND
J3 GND - C7 P2
C5
Capacitance
4.7uF
R1
Resistance
10kΩ
R2
Resistance
10kΩ
C2
Capacitance
22uF
R3
Resistance
10kΩ
C3
Capacitance
10uF
R4
Resistance
10kΩ
C6
End of Life
Capacitance
100nF
C7
Capacitance
1uF
C1
Capacitance
4.7uF
C4
Capacitance
1uF
J2
J3
  • Generic Inductor
    Generic Inductor
    A generic fixed inductor suitable for rapid circuit topology development. The footprint automatically adapts based on the selected package, supporting standard SMD sizes (e.g., 0402, 0603, 0805) as well as well-known inductor packages such as SDR1806, PA4320, SRN6028, and SRR1260. Standard inductor values: 1.0 nH, 10 nH, 100 nH, 1.0 µH, 10 µH, 100 µH, 1.0 mH 1.2 nH, 12 nH, 120 nH, 1.2 µH, 12 µH, 120 µH, 1.2 mH 1.5 nH, 15 nH, 150 nH, 1.5 µH, 15 µH, 150 µH, 1.5 mH 1.8 nH, 18 nH, 180 nH, 1.8 µH, 18 µH, 180 µH, 1.8 mH 2.2 nH, 22 nH, 220 nH, 2.2 µH, 22 µH, 220 µH, 2.2 mH 2.7 nH, 27 nH, 270 nH, 2.7 µH, 27 µH, 270 µH, 2.7 mH 3.3 nH, 33 nH, 330 nH, 3.3 µH, 33 µH, 330 µH, 3.3 mH 3.9 nH, 39 nH, 390 nH, 3.9 µH, 39 µH, 390 µH, 3.9 mH 4.7 nH, 47 nH, 470 nH, 4.7 µH, 47 µH, 470 µH, 4.7 mH 5.6 nH, 56 nH, 560 nH, 5.6 µH, 56 µH, 560 µH, 5.6 mH 6.8 nH, 68 nH, 680 nH, 6.8 µH, 68 µH, 680 µH, 6.8 mH 8.2 nH, 82 nH, 820 nH, 8.2 µH, 82 µH, 820 µH, 8.2 mH #generics #CommonPartsLibrary
    jharwinbarrozo
    16.2k
  • Generic Capacitor
    Generic Capacitor
    A generic fixed capacitor ideal for rapid circuit topology development. You can choose between polarized and non-polarized types, its symbol and the footprint will automatically adapt based on your selection. Supported options include standard SMD sizes for ceramic capacitors (e.g., 0402, 0603, 0805), SMD sizes for aluminum electrolytic capacitors, and through-hole footprints for polarized capacitors. Save precious design time by seamlessly add more information to this part (value, footprint, etc.) as it becomes available. Standard capacitor values: 1.0pF, 10pF, 100pF, 1000pF, 0.01uF, 0.1uF, 1.0uF, 10uF, 100uF, 1000uF, 10000uF 1.1pF, 11pF, 110pF, 1100pF 1.2pF, 12pF, 120pF, 1200pF 1.3pF, 13pF, 130pF, 1300pF 1.5pF, 15pF, 150pF, 1500pF, 0.015uF, 0.15uF, 1.5uF, 15uF, 150uF, 1500uF 1.6pF, 16pF, 160pF, 1600pF 1.8pF, 18pF, 180pF, 1800pF 2.0pF, 20pF, 200pF, 2000pF 2.2pF, 22pF, 220pF, 2200pF, 0.022uF, 0.22uF, 2.2uF, 22uF, 220uF, 2200uF 2.4pF, 24pF, 240pF, 2400pF 2.7pF, 27pF, 270pF, 2700pF 3.0pF, 30pF, 300pF, 3000pF 3.3pF, 33pF, 330pF, 3300pF, 0.033uF, 0.33uF, 3.3uF, 33uF, 330uF, 3300uF 3.6pF, 36pF, 360pF, 3600pF 3.9pF, 39pF, 390pF, 3900pF 4.3pF, 43pF, 430pF, 4300pF 4.7pF, 47pF, 470pF, 4700pF, 0.047uF, 0.47uF, 4.7uF, 47uF, 470uF, 4700uF 5.1pF, 51pF, 510pF, 5100pF 5.6pF, 56pF, 560pF, 5600pF 6.2pF, 62pF, 620pF, 6200pF 6.8pF, 68pF, 680pF, 6800pF, 0.068uF, 0.68uF, 6.8uF, 68uF, 680uF, 6800uF 7.5pF, 75pF, 750pF, 7500pF 8.2pF, 82pF, 820pF, 8200pF 9.1pF, 91pF, 910pF, 9100pF #generics #CommonPartsLibrary
    jharwinbarrozo
    1.5M
  • Generic Resistor
    Generic Resistor
    A generic fixed resistor ideal for rapid circuit topology development. Its footprint automatically adapts based on the selected package case code—supporting 0402, 0603, 0805, 1203, and many other standard SMD packages, as well as axial horizontal and vertical configurations. Save precious design time by seamlessly add more information to this part (value, footprint, etc.) as it becomes available. Standard resistor values: 1.0 ohm, 10 ohm, 100 ohm, 1.0k ohm, 10k ohm, 100k ohm, 1.0M ohm 1.1 ohm, 11 ohm, 110 ohm, 1.1k ohm, 11k ohm, 110k ohm, 1.1M ohm 1.2 ohm, 12 ohm, 120 ohm, 1.2k ohm, 12k ohm, 120k ohm, 1.2M ohm 1.3 ohm, 13 ohm, 130 ohm, 1.3k ohm, 13k ohm, 130k ohm, 1.3M ohm 1.5 ohm, 15 ohm, 150 ohm, 1.5k ohm, 15k ohm, 150k ohm, 1.5M ohm 1.6 ohm, 16 ohm, 160 ohm, 1.6k ohm, 16k ohm, 160k ohm, 1.6M ohm 1.8 ohm, 18 ohm, 180 ohm, 1.8K ohm, 18k ohm, 180k ohm, 1.8M ohm 2.0 ohm, 20 ohm, 200 ohm, 2.0k ohm, 20k ohm, 200k ohm, 2.0M ohm 2.2 ohm, 22 ohm, 220 ohm, 2.2k ohm, 22k ohm, 220k ohm, 2.2M ohm 2.4 ohm, 24 ohm, 240 ohm, 2.4k ohm, 24k ohm, 240k ohm, 2.4M ohm 2.7 ohm, 27 ohm, 270 ohm, 2.7k ohm, 27k ohm, 270k ohm, 2.7M ohm 3.0 ohm, 30 ohm, 300 ohm, 3.0K ohm, 30K ohm, 300K ohm, 3.0M ohm 3.3 ohm, 33 ohm, 330 ohm, 3.3k ohm, 33k ohm, 330k ohm, 3.3M ohm 3.6 ohm, 36 ohm, 360 ohm, 3.6k ohm, 36k ohm, 360k ohm, 3.6M ohm 3.9 ohm, 39 ohm, 390 ohm, 3.9k ohm, 39k ohm, 390k ohm, 3.9M ohm 4.3 ohm, 43 ohm, 430 ohm, 4.3k ohm, 43K ohm, 430K ohm, 4.3M ohm 4.7 ohm, 47 ohm, 470 ohm, 4.7k ohm, 47k ohm, 470k ohm, 4.7M ohm 5.1 ohm, 51 ohm, 510 ohm, 5.1k ohm, 51k ohm, 510k ohm, 5.1M ohm 5.6 ohm, 56 ohm, 560 ohm, 5.6k ohm, 56k ohm, 560k ohm, 5.6M ohm 6.2 ohm, 62 ohm, 620 ohm, 6.2k ohm, 62K ohm, 620K ohm, 6.2M ohm 6.8 ohm, 68 ohm, 680 ohm, 6.8k ohm, 68k ohm, 680k ohm, 6.8M ohm 7.5 ohm, 75 ohm, 750 ohm, 7.5k ohm, 75k ohm, 750k ohm, 7.5M ohm 8.2 ohm, 82 ohm, 820 ohm, 8.2k ohm, 82k ohm, 820k ohm, 8.2M ohm 9.1 ohm, 91 ohm, 910 ohm, 9.1k ohm, 91k ohm, 910k ohm, 9.1M ohm #generics #CommonPartsLibrary
    jharwinbarrozo
    1.5M
  • Ground
    Ground
    A common return path for electric current. Commonly known as ground.
    jharwinbarrozo
    20.5M
  • Terminal
    Terminal
    An electrical connector acting as reusable interface to a conductor and creating a point where external circuits can be connected.
    natarius
  • Net Portal
    Net Portal
    Wirelessly connects nets on schematic. Used to organize schematics and separate functional blocks. To wirelessly connect net portals, give them same designator. #portal
    jharwinbarrozo
    43.0M
  • RMCF0805JT47K0
    RMCF0805JT47K0
    General Purpose Thick Film Standard Power and High-Power Chip Resistor 47 kOhms ±5% 0.125W, 1/8W Chip Resistor 0805 (2012 Metric) Automotive AEC-Q200 Thick Film Features: - RMCF – standard power ratings - RMCP – high power ratings - Nickel barrier terminations standard - Power derating from 100% at 70ºC to zero at +155ºC - RoHS compliant, REACH compliant, and halogen free - AEC-Q200 compliant
    jharwinbarrozo
    1.2M
  • 875105359001
    875105359001
    10 µF 16 V Aluminum - Polymer Capacitors Radial, Can - SMD 30mOhm 2000 Hrs @ 105°C #commonpartslibrary #capacitor #aluminumpolymer #radialcan
    jharwinbarrozo
    1.2M
  • CTL1206FYW1T
    CTL1206FYW1T
    Yellow 595nm LED Indication - Discrete 1.7V 1206 (3216 Metric)
    jharwinbarrozo
    1.1M
  • 1070TR
    1070TR
    Battery Holder (Open) Coin, 20.0mm 1 Cell SMD (SMT) Tab bate or batt #forLedBlink
    jharwinbarrozo
    700.5k

Fathom-X ESP32 WiFi Bridge

Fathom-X ESP32 WiFi Bridge thumbnail
48V tether-powered Ethernet-to-WiFi bridge using Blue Robotics Fathom-X style tether interface and ESP32-S3 WiFi output, with isolated/buck DC/DC rails for the tether interface and ESP32.

Properties

Properties describe core aspects of the project.

Pricing & Availability

Distributor

Qty 1

Arrow

$55.67–$60.36

Digi-Key

$63.36–$63.36

HQonline

$3.13

LCSC

$71.18–$73.07

Mouser

$67.12

TME

$1.49

Verical

$46.58–$336.78

Controls