232211 - EverTag Ext LTE US¶
| Article Number | 232211 |
| Name | EverTag Extension PCB LTE US |
| Base PCB | Connects to 232203 Base Bat+WiFi via board-to-board connector |
| LTE Modem | SIMCom SIM7672NA (LTE Cat-1bis, Qualcomm QCX216) |
| Region | US / North America (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 (232203 with B2B connector) and enclosure (232506) are designed to accommodate this board in a future iteration.
1. Overview¶
The 232211 is the US/North America variant of the LTE extension PCB. It is electrically and mechanically identical to the 232210 EU variant, differing only in the LTE modem IC. The SIM7672NA replaces the SIM7672E to provide US LTE band coverage. Both modems are pin-compatible within the SIMCom SIM7672 family — same package, same pinout, same chipset, same AT command set.
Key Differences from 232210 (EU)¶
| Parameter | 232210 (EU) | 232211 (US) |
|---|---|---|
| LTE Modem | SIMCom SIM7672E | SIMCom SIM7672NA |
| Certification | CE-RED | FCC (ID: 2AJYU-8XS0003) |
| LTE Bands | B1, B3, B7, B8, B20, B28 | B2, B4, B5, B12, B13, B25, B26, B66 |
| Target Market | EU (Nordic, DACH, Benelux) | US, Canada, Mexico |
Shared with 232210 (EU) — No Changes¶
The following are identical between 232210 and 232211. For full details (schematics, pin tables, component selection, design notes), refer to 232210:
| Subsystem | Shared Part | 232210 Reference |
|---|---|---|
| B2B Connectors | Samtec TMM/SFM 1.27 mm, 2× (2×8) = 32 pins | §3.2 |
| B2B Pin Assignment | 32-pin dual split (B2B-L power+GND, B2B-R signals+GND) | §3.2 |
| SIM Card Holder | GCT SIM8075-6-1-12-00-A | §3.3 |
| Chip Antenna | Quectel YC0001CA (wideband, covers US bands, left-edge placement) | §3.4 |
| U.FL Test Port | Hirose U.FL-R-SMT-1(10) (DNP) | §3.5 |
| 3.8V LDO | Microchip MIC29302WU-TR (3A adj) | §3.6 |
| Level Shifters | TI TXB0106PWR (1.8V↔3.3V) | §3.7 |
| NPN Drivers | BSS138 × 2 (PWRKEY, RESET) | §5.10 |
| SIM ESD | Nexperia PRTR5V0U2X × 2 | §5.11 |
| NETLIGHT LED | 0402 green + 1k (DNP in prod) | §3.8 |
| Bulk Caps | 2× 22 µF ceramic + 100 µF tantalum | §5.9 |
| PCB Layout | 4-layer, black mask, ENIG, top-only | §6 |
| Test Points | TP40–TP48 | §7 |
| ESP32 GPIO Mapping | GPIO0–5, 15, 25 | Signal Path Table |
Same Gerber, Different BOM
Since the SIM7672E and SIM7672NA are pin-compatible (same 24×24 mm LCC+LGA footprint), the same Gerber files are used for both 232210 and 232211. Only the assembly BOM line for the modem IC changes.
2. Block Diagram¶
Same as 232210 Block Diagram, with SIM7672NA replacing SIM7672E.
graph TB
subgraph base [232203 Base PCB]
ESP32["ESP32-C5 WROOM<br/>(3.3V logic)"]
PWR_5V["5V / 2A Rail"]
B2B_BASE_L["B2B-L Header (left of WiFi)"]
B2B_BASE_R["B2B-R Header (right of WiFi)"]
end
subgraph ext [232211 Extension PCB - US variant]
B2B_EXT_L["B2B-L Socket (power+GND)"]
B2B_EXT_R["B2B-R Socket (signals+GND)"]
LDO38["3.8V LDO<br/>MIC29302"]
LVLSHIFT["TXB0106<br/>1.8V↔3.3V"]
MODEM["SIMCom SIM7672NA<br/>(1.8V I/O, US bands)"]
SIM["Nano-SIM 4FF Holder"]
CHIP_ANT["Quectel YC0001CA<br/>Chip Antenna"]
UFL["U.FL (test/fallback)"]
LED_NET["NETLIGHT LED (DNP)"]
end
PWR_5V --> B2B_BASE_L
ESP32 <-->|"LTE UART + control<br/>(3.3V)"| B2B_BASE_R
B2B_BASE_L <-->|"16-pin B2B-L"| B2B_EXT_L
B2B_BASE_R <-->|"16-pin B2B-R"| B2B_EXT_R
B2B_EXT_L -->|"5V"| LDO38
LDO38 -->|"3.8V VBAT"| MODEM
B2B_EXT_R <-->|"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_NET3. LTE Modem — SIMCom SIM7672NA (Delta)¶
3.1 Module Specification¶
| Parameter | Value |
|---|---|
| Manufacturer | SIMCom |
| Part Number | SIM7672NA |
| Chipset | Qualcomm QCX216 (same as SIM7672E) |
| Technology | LTE Cat-1bis (single RX antenna) |
| Region | US / North America |
| Certification | FCC (ID: 2AJYU-8XS0003) |
| LTE Bands | B2, B4, B5, B12, B13, B25, B26, B66 |
| Interface | UART (AT commands), all I/O at 1.8V logic level |
| Supply | 3.4–4.2V (VBAT pins), typical 3.8V |
| Peak Current | Up to 2A during TX burst |
| Sleep Current | <1 mA (SLEEP1 mode, DTR high, USB disconnected) |
| Package | LCC+LGA, 24 × 24 × 2.4 mm (pin-compatible with SIM7672E) |
| Est. Price | ~$7–10 @ 1k volume |
3.2 Pin Compatibility Confirmation¶
The SIM7672NA uses the exact same pinout as the SIM7672E. All pins documented in the 232210 modem pin assignment and signal path table apply without change:
| Pin # | Name | Function | Same as SIM7672E? |
|---|---|---|---|
| 1 | PWRKEY | Power on/off toggle | ✅ Identical |
| 9 | MAIN_UART_TXD | AT response data from modem | ✅ Identical |
| 10 | MAIN_UART_RXD | AT command data to modem | ✅ Identical |
| 15 | VDD_EXT (1.8V) | Level shifter reference supply | ✅ Identical |
| 38 | NRST | Hardware reset | ✅ Identical |
| 52 | NETLIGHT | Network status LED output | ✅ Identical |
| 55–57 | VBAT | 3.8V power supply | ✅ Identical |
| 60 | RF_ANT | 50 Ω RF output | ✅ Identical |
| 66 | STATUS | Module active indicator | ✅ Identical |
| 6 | USB_BOOT | Strapping (NC/pull-up) | ✅ Identical |
AT Command Compatibility
The SIM7672NA uses the same AT command set as the SIM7672E. Firmware does not need any changes between EU and US variants. Band selection is automatic based on the SIM card's PLMN list and modem's supported bands.
3.3 US LTE Band Coverage¶
| Band | Frequency (MHz) | Bandwidth | US Carriers | Coverage Type |
|---|---|---|---|---|
| B2 | 1900 (PCS) | 5–20 MHz | T-Mobile, AT&T | Urban/suburban mid-band |
| B4 | 1700/2100 (AWS) | 5–20 MHz | T-Mobile, AT&T, Verizon (LTE) | Urban high-capacity |
| B5 | 850 (CLR) | 5–10 MHz | AT&T, US Cellular | Rural, legacy coverage |
| B12 | 700a (lower) | 5–10 MHz | T-Mobile | Rural, building penetration |
| B13 | 700c (upper) | 10 MHz | Verizon (primary low-band) | Nationwide Verizon LTE |
| B25 | 1900 (ext PCS) | 5–15 MHz | Sprint/T-Mobile | Extended PCS |
| B26 | 850 (ext CLR) | 5–10 MHz | Sprint/T-Mobile | Extended 850 MHz |
| B66 | 1700/2100 (ext AWS) | 10–20 MHz | T-Mobile, AT&T | Extended AWS |
Three-Carrier Coverage
The SIM7672NA band selection covers all three major US carriers:
- T-Mobile: B2, B4, B12, B25, B66 (excellent coverage)
- AT&T: B2, B4, B5, B66 (good coverage)
- Verizon: B4, B13 (basic LTE coverage — Verizon requires separate CDMA-less certification)
Verizon Certification
Verizon requires devices using B13 to pass Open Development device certification. This is a separate process from FCC certification. The SIM7672NA module itself is FCC-certified, but the end product may require additional Verizon OD approval for B13 operation. If Verizon support is not needed initially, B13 can be disabled via AT command (AT+CBANDCFG).
3.4 Antenna Coverage Confirmation¶
The Quectel YC0001CA chip antenna covers 698–960 MHz and 1710–2700 MHz, which includes all SIM7672NA bands:
| US Band | Frequency (MHz) | Antenna Coverage |
|---|---|---|
| B2 | 1850–1990 | ✅ (1710–2700) |
| B4 | 1710–2155 | ✅ (1710–2700) |
| B5 | 824–894 | ✅ (698–960) |
| B12 | 699–746 | ✅ (698–960) |
| B13 | 746–787 | ✅ (698–960) |
| B25 | 1850–1995 | ✅ (1710–2700) |
| B26 | 814–894 | ✅ (698–960) |
| B66 | 1710–2200 | ✅ (1710–2700) |
All US bands are within the chip antenna's operating range. No antenna change is required between the EU and US variants.
4. Component Selection (Delta)¶
Only the LTE modem differs from the 232210 BOM. All other components are identical.
4.1 LTE Modem¶
| Parameter | Value |
|---|---|
| Manufacturer | SIMCom |
| Part Number | SIM7672NA |
| Package | LCC+LGA, 24 × 24 × 2.4 mm |
| Est. Price | ~$7–10 @ 1k volume |
Supplier Links:
| Source | Part Number / Link | Notes |
|---|---|---|
| SIMCom | SIM7672 Series | Manufacturer direct — select SIM7672NA variant |
| DigiKey | Search SIM7672NA | Via SIMCom at DigiKey |
| LCSC | Search SIM7672NA | Check availability |
| Texim Europe | SIMCom modules | EU-based distributor, ships globally |
Alternative modules (pin-compatible, same footprint):
| Module | Bands | Key Difference |
|---|---|---|
| SIM7672G | Global (incl. B2, B4, B5, B12, B13, B25, B26, B28, B66) | Superset of both EU and US bands. Higher cost, but eliminates the need for two variants. |
| A7672SA-FASE | B2, B4, B5, B7, B12, B13, B25, B26, B66 | ASR1603 chipset, cheaper but higher sleep current (~3 mA) |
Consider SIM7672G for Single-SKU Strategy
If production volumes are low (<5k units), using the SIM7672G (global bands) for both EU and US variants eliminates the need for two separate BOMs. Same footprint, same AT commands. The only trade-off is slightly higher module cost (~$1–2 more). The chip antenna (YC0001CA) already covers all global bands.
4.2 All Other Components¶
Identical to 232210. Refer to 232210 §5.2–5.11 for complete part numbers, supplier links, and sourcing:
| # | Component | Part Number | Reference |
|---|---|---|---|
| 5.2 | B2B Connectors (×2) | Samtec SFM-108-01-x-D (1.27 mm) | 232210 §5.2 |
| 5.3 | SIM Holder | GCT SIM8075-6-1-12-00-A | 232210 §5.3 |
| 5.4 | Chip Antenna | Quectel YC0001CA | 232210 §5.4 |
| 5.5 | U.FL (DNP) | Hirose U.FL-R-SMT-1(10) | 232210 §5.5 |
| 5.6 | 3.8V LDO | Microchip MIC29302WU-TR | 232210 §5.6 |
| 5.7 | Level Shifter | TI TXB0106PWR | 232210 §5.7 |
| 5.8 | NETLIGHT LED (DNP) | 0402 green + 1k | 232210 §5.8 |
| 5.9 | Bulk Caps | 2× 22 µF + 100 µF tant. | 232210 §5.9 |
| 5.10 | MOSFET Drivers | BSS138 × 2 | 232210 §5.10 |
| 5.11 | SIM ESD | PRTR5V0U2X × 2 | 232210 §5.11 |
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 are used for both variants. Only the BOM changes (modem IC swap).
Key specifications (see 232210 §6 for full details):
- 4-layer FR4, black solder mask, ENIG finish
- All components on top side only
- Chip antenna at board edge with 5 mm keep-out zone
- VBAT traces ≥3 mm wide
- 50 Ω controlled impedance RF trace
6. Test Points¶
Same test points as 232210 §7 (TP40–TP48).
US-Specific Tests¶
All 232210 test procedures apply. Additional US-specific tests:
- Insert US-carrier SIM card (T-Mobile, AT&T, or Verizon)
-
AT+CREG?→ returns registered on US network (0,1 or 0,5) -
AT+CSQ→ signal quality within acceptable range (RSSI > 10) -
AT+COPS=?→ verify B12 (T-Mobile) or B13 (Verizon) visible -
AT+CBANDCFG="CAT-M"→ confirm US bands active (B2, B4, B5, B12, B13, B25, B26, B66) - TCP data test through US carrier network
- Signal quality comparison: chip antenna vs U.FL + external FPC antenna
- Sleep current measurement:
AT+CSCLK=1, DTR high → verify <1 mA - Multi-carrier test: repeat registration and data test with SIMs from at least 2 different US carriers
Verizon B13 Testing
If Verizon B13 operation is intended, verify that the end product passes Verizon Open Development certification. The module-level FCC cert is necessary but not sufficient for B13. For initial prototype testing, use T-Mobile or AT&T SIM cards (no carrier-specific device certification required).
7. Revision History¶
| Revision | Date | Author | Changes |
|---|---|---|---|
| Rev A | TBD | TBD | Initial design (not in first PCB iteration) |
Related Documents¶
- 232203 Base Bat+WiFi — Base PCB this extension connects to
- 232210 Ext LTE EU — EU variant — master specification (full schematics, pinout, component selection, design notes)
- ADR #17: LTE Module and Antenna — Decision rationale
- Sales Articles — Part of subassembly 232505 (US)
datasheets/A7672 Series_Spec_20230418.pdf— SIMCom modem pinout reference (pin-compatible family)datasheets/A7670_SIM7070_A7672X_Compatible_Design_V1.02.pdf— SIMCom hardware design referencedatasheets/SIM7672X_Sleep_Mode_Application_Note_V1.00.pdf— Sleep mode configuration