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232211 - EverTag Ext LTE US
Article Number 232211
Name EverTag Extension PCB LTE US
Base PCB Connects to 232204 Base Full via board-to-board connector
LTE Modem SIMCom SIM7672NA (LTE Cat-1bis, Qualcomm QCX216)
Region US (FCC)
Status Not included in the first PCB iteration

Not in First PCB Iteration

This extension PCB is fully specified but is not included in the first PCB production run. The base platform (232204) and enclosure (232506) are designed to accommodate this board in a future iteration.

1. Overview

The 232211 is the US-market variant of the LTE extension PCB, functionally identical to the 232210 EU variant but using the SIMCom SIM7672NA modem with US LTE band support. It stacks on top of the 232204 base PCB via a board-to-board connector.

Key Differences from 232210 (EU)

Parameter 232210 (EU) 232211 (US)
LTE Modem SIMCom SIM7672E SIMCom SIM7672NA
Certification CE-RED FCC
LTE Bands B1, B3, B7, B8, B20, B28 B2, B4, B5, B12, B13, B25, B26, B66
Antenna Same (Quectel YC0001CA on-board) Same (Quectel YC0001CA on-board)

Shared Design

The PCB layout, board-to-board connector (Harwin M20, 14-pin), SIM holder, on-board chip antenna (Quectel YC0001CA), U.FL test port, 3.8V LDO, level shifters (1.8V↔3.3V), NETLIGHT dev LED, RF design, and component placement are identical between 232210 and 232211. The only difference is the LTE modem IC (SIM7672E vs SIM7672NA). Both modems are pin-compatible within the SIMCom SIM7672 family -- same Qualcomm QCX216 chipset, same AT commands, same power and interface requirements.

For full schematic details, B2B connector pin-out, SIM holder, level shifter design, power supply, component placement rules, and test procedures, refer to the 232210 EU documentation. This document covers only the US-specific differences.

2. Block Diagram

Same as 232210 Block Diagram, with SIM7672NA replacing SIM7672E.

graph TB
    subgraph base [232204 Base PCB]
        ESP32["ESP32-C5 WROOM<br/>(3.3V logic)"]
        PWR_5V["5V / 2A Rail"]
        B2B_BASE["B2B Header: Harwin M20"]
    end

    subgraph ext [232211 Extension PCB - all components top side]
        B2B_EXT["B2B Socket: Harwin M20"]
        LDO38["3.8V LDO"]
        LVLSHIFT["1.8V↔3.3V<br/>Level Shifters"]
        MODEM["SIMCom SIM7672NA<br/>(1.8V I/O)"]
        SIM["Nano-SIM 4FF Holder"]
        CHIP_ANT["On-Board Chip Antenna<br/>Quectel YC0001CA"]
        UFL["U.FL (test/fallback)"]
        LED_NET["NETLIGHT LED (DNP in prod)"]
    end

    PWR_5V --> B2B_BASE
    ESP32 <-->|"LTE UART + control<br/>(3.3V)"| B2B_BASE
    B2B_BASE <-->|"14-pin B2B"| B2B_EXT

    B2B_EXT -->|"5V"| LDO38
    LDO38 -->|"3.8V VBAT"| MODEM
    B2B_EXT <-->|"3.3V signals"| LVLSHIFT
    LVLSHIFT <-->|"1.8V signals"| MODEM

    MODEM <--> SIM
    MODEM -->|"RF"| CHIP_ANT
    MODEM -.->|"RF (alt)"| UFL
    MODEM -.->|"NETLIGHT"| LVLSHIFT
    MODEM -.->|"NETLIGHT"| LED_NET

3. LTE Modem -- SIMCom SIM7672NA

Parameter Value
Manufacturer SIMCom
Part Number SIM7672NA
Chipset Qualcomm QCX216
Technology LTE Cat-1bis
Region US (FCC certified)
LTE Bands B2, B4, B5, B12, B13, B25, B26, B66
Interface UART (AT commands), 1.8V logic
Supply 3.4--4.2V (same as SIM7672E)
Peak Current Up to 2A during TX burst
Package LCC+LGA, 24 x 24 x 2.4 mm (pin-compatible with SIM7672E)
Est. Price ~$7--10 @ 1k volume

Rationale:

  • Same SIMCom SIM7672 platform as EU variant -- shared firmware AT command interface
  • Pin-compatible with SIM7672E -- identical PCB layout, only BOM change
  • US LTE band coverage for major carriers (AT&T, T-Mobile, Verizon)
  • FCC pre-certified module
  • Same Qualcomm QCX216 chipset, same low sleep current (<1 mA)

Supplier Link: SIMCom SIM7672 Series

4. Antenna

Same on-board chip antenna as 232210:

Parameter Value
Part Number Quectel YC0001CA
Frequency 698--960 MHz / 1710--2700 MHz
Type SMD chip antenna (reflow)

The wideband chip antenna covers both EU and US LTE frequency ranges, enabling the same antenna for both regional variants. The U.FL test/fallback connector is also identical.

5. PCB Design Notes

The PCB layout is identical to the 232210 EU variant. Since the SIM7672E and SIM7672NA are pin-compatible, the same Gerber files can be used for both variants. Only the BOM changes (modem IC swap). All other components (LDO, level shifters, chip antenna, SIM holder, capacitors, U.FL) are identical.

6. Test Points

Same test points as 232210.

US-Specific Tests

  • All tests from 232210 test plan with US SIM card
  • LTE bands: verify registration on US carriers
  • AT+CREG? returns registered on US network
  • AT+CSQ signal quality within acceptable range for US deployment area
  • Band verification: AT+COPS=? shows B12 or B13 available (Verizon/T-Mobile low-band)

7. Revision History

Revision Date Author Changes
Rev A TBD TBD Initial design (not in first PCB iteration)