EC800M-CN Breakout Design

flux

2:19

Planning for component integration.

Organizing component connections.

Deciding on ERC resolution.

Planning for ERC resolution.

Formulating ERC and connection instructions.

Creating connection instructions.

I can’t directly clear ERC in your project, but I can give you a complete, datasheet-aligned connection checklist so everything is wired correctly and ERC will pass once MPNs are assigned and the EC800M-CN symbol is added.
Follow these connections and notes exactly
Power and VBAT rail
  • Regulator: Configure U2 TPS62130 to 3.8 V (Vout = 0.8 V × (1 + R1/R2)). Typical pair: R1=37.5 kΩ, R2=10 kΩ.
  • VBAT feed to modem: Tie both Modem_Conn VBAT_42 and VBAT_43 portals to U2’s 3.8 V output and to the VBAT bulk/decoupling cluster: C13, C14 (bulk), plus C15 1 µF and C4 100 nF to GND.
  • VBAT debug link: Insert R6 = 0 Ω in series near the modem pins (or as a shunt link) for current probing. Keep VBAT copper ≥ 2 mm width.
  • VDD_EXT (1.8 V ref, pin 24): Connect Modem_Conn VDD_EXT_24 to U3 TXS0108E VCCA. Connect U3 VCCB to U1 3V3.
  • Ground: Tie all Modem_Conn GND portals to GND. Ensure solid plane under the module area.
Level shifting (all modem I/O is 1.8 V)
  • Use U3 TXS0108E.
  • A-side (1.8 V, VCCA=VDD_EXT_24): connect to these Modem_Conn portals:
    • PWRKEY_7, RESET_N_15, NET_STATUS_16, STATUS_25
    • MAIN_RXD_17, MAIN_TXD_18, MAIN_DTR_19, MAIN_RI_20, MAIN_DCD_21, MAIN_CTS_22, MAIN_RTS_23
  • B-side (3.3 V, VCCB=3V3): route to U1 through the stacking headers J4/J5. Use UART0 TXD0/RXD0 for MAIN_RXD/MAIN_TXD and assign RTS/CTS/DTR/RI/DCD/STATUS/PWRKEY/RESET to non-bootstrapping GPIOs. Keep PWRKEY and RESET_N total load < 10 nF. Add labeled test pads where helpful.
SIM interface (USIM1)
  • Series links: Route Modem_Conn USIM1_DATA_11, USIM1_RST_12, USIM1_CLK_13, USIM1_VDD_14, USIM1_DET_79 via 0 Ω series resistors R7–R11 to the nano‑SIM J1 pins (I/O, RST, CLK, VCC, DET).
  • ESD: Protect the five SIM nets with D4 (COM to GND).
  • Pull-ups: Place 15 kΩ near J1 (use R12, R13, R14) on SIM_IO/SIM_CLK/SIM_RST per the EC800M-CN reference.
  • Shunt caps: Place 33 pF C0G to ground on SIM_IO/CLK/RST: C16, C17, C18.
  • Decoupling: Add 100 nF from SIM_VDD to GND at J1 (you can repurpose C18 or add a dedicated 100 nF close to J1 VCC).
  • Presence: Add 51 kΩ R15 for SIM_DET per your connector’s detect scheme. Keep traces short and guarded with ground.
RF and antenna
  • From Modem_Conn ANT_MAIN_35 feed the π‑match Cpi1–Lpi–Cpi2. Default C’s can be DNP; tune at bring‑up. Keep the network tight to the feed.
  • To chip antenna: route from the π‑match output to ANT1 with 50 Ω, stitched ground fences, and top‑layer keepout under the antenna body.
  • U.FL option: keep a 0 Ω branch R1 from the feed to J3 Center_Contact so you can select external antenna. Do not populate both paths simultaneously.
  • Antenna ESD: If used, keep C19 DNP or choose a device with Cj ≤ 0.05 pF right at the feed.
USB (optional, from modem)
  • Differential lines: Route Modem_Conn USB_DP_59 and USB_DM_60 through the common‑mode choke L2, then 0 Ω jumpers R16/R17, to the USB‑C J6 D+ and D− pins. Maintain 90 Ω differential.
  • ESD: Protect D+/D− with D5; COM to GND. Choose TVS Cj < 1 pF per line.
  • VBUS detect: Tie Modem_Conn USB_VBUS_61 to 5 V through J6:VBUS and a link (0 Ω for bring‑up). COM ground stitching close to the connector.
Stacking headers and ESP32 mapping
  • Use J4/J5 to mate with U1. Bring up:
    • 5 V to U2 input, GND, 3V3 to U3 VCCB, UART0 TXD0/RXD0, RTS/CTS, DTR/RI/DCD, NET_STATUS/STATUS, PWRKEY, RESET_N.
  • Keep all ESP32 bootstrap pins safe (no hard pulls that alter boot mode). Use series resistors or ensure default-high/low per ESP32 guidance.
To actually clear ERC now
  • I can assign the missing MPNs and set Exclude-from-BOM where needed (test pads, stacking sockets) if you want me to make those edits in your project. Say “Assign MPNs now” and I’ll proceed to update properties and re-run ERC.
  • Otherwise, once you confirm all the connections above are in place, re-run ERC. The only remaining items should be MPNs or any leftover unconnected Modem_Conn portals.
If you prefer, I can also provide a compact pin-to-pin checklist (one line per signal) for quick verification against your Modem_Conn portals.
Share ERC errors
Pick modem symbol
Fix PWRKEY/RESET
Verify SIM wiring
Level shifter choice
90 days
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  • Ground
    Ground
    A common return path for electric current. Commonly known as ground.
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    Wirelessly connects power nets on schematic. Identical to the net portal, but with a power symbol. Used to organize schematics and separate functional blocks. To wirelessly connect power net portals, give them the same designator. #portal #power
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    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
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    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
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Puzzled Lavender Robot Maid thumbnail
Integration of EC800M-CN LTE Module via Modem_Conn Placeholders on ESP32-DevKitC Carrier with Parked Power, Control, SIM, RF, and USB Nets

Properties

Diagram



  
    
  
  
    
  








UART/Control

VBAT

SIM_VCC, SIM_IO, SIM_CLK, SIM_RST

RF_OUT

RF_OUT

USB D+/D-







ESP32-DevKitC
TPS62130ARGTR VBAT Regulator
EC800M-CN Modem
SMN-305 Nano-SIM Holder
Chip Antenna with Pi-Match Network
U.FL Connector with 0 Ohm Link
Optional USB Interface

Pricing & Availability

Distributor

Qty 1

Arrow

$9.10–$13.25

Digi-Key

$25.70–$29.11

LCSC

$8.77–$8.82

Mouser

$15.78

TME

$6.75

Verical

$8.24–$19.16

Controls