Fathom-X WiFi Bridge Design


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:
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.
is this a two layer or 4 layer board?
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

Schematic of Fathom-X ESP32 WiFi Bridge
U4
U4 VDD2P0 - C11 P1
PS2 OUT - U1 VIN
T1 PL_L - J2 1
T1 PL_L - J2 1
C20 P2 - U4 PETX_N
U7 V3 - C6 P1
U2 IO45 - R3 P1
T1 PL_L - J2 1
PS1 +VOUT - PS2 IN
J3 CC1 - R5 P1
J1 PIN1 - PS1 +VIN
J3 CC1 - R5 P1
J3 CC2 - R6 P1
U4 TX- - T1 TX-
T1 PL_N - J2 2
U7 V3 - C6 P1
U7 V3 - C6 P1
T1 PL_N - J2 2
U7 ~RTS - U2 EN
J3 DP2 - U7 UD+
C18 P2 - U4 PERX_N
U7 ~DTR - U2 IO0
U7 ~RTS - U2 EN
U4 VDD2P0 - C11 P1
J3 DN2 - U7 UD-
U4 RX- - T1 RX-
J3 CC2 - R6 P1
U2 IO46 - R4 P1
PS2 OUT - U1 VIN
U7 V3 - C6 P1
J3 GND - C7 P2
J3 GND - C7 P2
J3 GND - C7 P2
U3 GND - J3 GND
J3
GND
GND
GND
GND
GND
GND
PS3 GND - U5 GND
PS3 GND - U5 GND
GND
J3 GND - C7 P2
C5
Capacitance
4.7uF
R1
Resistance
10kΩ
R6
Resistance
5.1kΩ
R2
Resistance
10kΩ
C2
Capacitance
22uF
R3
Resistance
10kΩ
C11
End of Life
Capacitance
0.1uF
C3
Capacitance
10uF
C12
Not Recommended for New Designs
Capacitance
330pF
J2
R7
Resistance
10Ω
R4
Resistance
10kΩ
C6
End of Life
Capacitance
100nF
C7
Capacitance
1uF
R5
Resistance
5.1kΩ
C1
Capacitance
4.7uF
C4
Capacitance
1uF
D2

Fathom-X ESP32 WiFi Bridge

Fathom-X ESP32 WiFi Bridge thumbnail