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[DOC] MCU Hardware Comparison

Development Boards

Feature Heltec v4 (Low Power) Heltec v4 (High Power) LilyGO T3-S3 SX1262 Seeed XIAO + Wio-SX1262 RAK WisBlock (RAK4631 + Base)
MCU ESP32-S3R2 (240 MHz dual-core, Wi-Fi/BLE) ESP32-S3R2 (240 MHz dual-core, Wi-Fi/BLE) ESP32-S3 (240 MHz dual-core, Wi-Fi/BLE) nRF52840 (64 MHz, BLE only) nRF52840 (64 MHz, BLE only)
LoRa Radio Semtech SX1262 (433, 470-510, 863-928MHz, +21 ±1 dBm PA, -137dBm RX) Semtech SX1262 (863-928MHz, +28 ±1 dBm PA, -137dBm RX) Semtech SX1262 (915 MHz, +22 dBm PA, –148 dBm RX) Semtech SX1262 (915 MHz, +22 dBm PA, –148 dBm RX) Semtech SX1262 (915 MHz, +22 dBm PA, –148 dBm RX)
Antenna Connector 2 × U.FL (LoRa & 2.4 GHz) 2 × U.FL (LoRa & 2.4 GHz) SMA-female (50 Ω) U.FL (50 Ω) U.FL on module (via Base board breakout)
RF Shielding

❌ No metal can ✅ Metal RF can over SX1262 ✅ Metal RF can over SX1262
Frequency Reference Standard crystal (XO) Standard crystal (XO) Standard crystal (XO) TCXO TCXO
TX/RX Switch Passive LC network (no RF-switch IC) RF front-end module (GC1109) with T/R paths (PA_CSD/CPS/CTX control) Passive LC network or discrete FET (auto via DIO2) SPDT RF switch IC (controlled by RF_SW/DIO2) SPDT RF switch IC (controlled by DIO2)
Matching & Filtering On-board LC network + low-pass filter On-board LC network + π-attenuator (≈17 dB) in RF path On-board LC network + low-pass filter On-module LC network + low-pass filter On-module LC network + low-pass filter
External LNA ❌ No ✅ Yes (in GC1109 FEM) ❌ No ❌ No ❌ No
Power Regulation (3.3 V) CE6260B33M rails (U1/U2) Multiple LDOs: CE6260B33M rails (U1/U2) + TLV75733 “Vfem” for FEM Single LDO (from USB or LiPo) 5 V→3.3 V regulator + internal DC-DC for PA 5 V→3.3 V regulator + internal DC-DC for PA
PA Supply Path 3.3 V → SX1262 DC-DC (inductor L13) → VR_PA pins TLV75733 3.3 V → “Vfem” → GC1109 VCC0/VCC1 3.3 V LDO → PA pins 3.3 V regulator → SX1262 DC-DC → PA pins 3.3 V regulator → SX1262 DC-DC → PA pins
Battery Input 1.25*2 Pin Lithium connector (3.3–4.4 V) 1.25*2 Pin Lithium connector (3.3–4.4 V) LiPo connector (powers 3.3 V rail) LiPo connector (powers 3.3 V rail) LiPo connector (powers 3.3 V rail)
USB-Only Full TX Power ✅ Yes ✅ Yes ✅ Yes ✅ Yes ✅ Yes
Low-Voltage Boost ❌ No (LDO-only; no boost converter shown in datasheet) ❌ No (LDO-only; no boost converter shown in datasheet) ❌ No (LDO needs ≥~3.8 V in) ✅ SX1262 DC-DC can run down to ~3.3 V input ✅ SX1262 DC-DC can run down to ~3.3 V input
USB and Battery Power Feed USB feeds charger/regulators; LiPo auto-switchover via CN3165 + MOSFETs (Q1/Q2/Q3, D2) USB feeds charger/regulators; LiPo auto-switchover via CN3165 + MOSFETs (Q1/Q2/Q3, D2) Both battery & USB feed the same 3.3 V LDO input USB feeds regulator and charger; LiPo auto-switchover USB feeds Base’s regulator & charger; LiPo auto-switchover
MCU Wireless Wi-Fi + BLE + LoRa Wi-Fi + BLE + LoRa Wi-Fi + BLE + LoRa BLE + LoRa BLE + LoRa
On-board Display ✅ 0.96″ OLED (SSD1315) ✅ 0.96″ OLED (SSD1315) ✅ 0.96″ OLED ❌ No ❌ No
Typical Board Size 51.7 × 25.4 × 10.7 mm 51.7 × 25.4 × 10.7 mm ~67 × 29 mm ~21 × 18 mm (XIAO) + 11 × 6 mm module Base ~60 × 24 mm + module ~27 × 15 mm

Legend/Notes:

  • RF shielding can: a metal can over the RF module to reduce EMI.

  • XO vs. TCXO: crystal oscillators; TCXO provides better frequency stability over temperature.

  • DC-DC for PA: SX1262’s internal switching regulator mode, drawing less current from the 3.3 V rail.

  • Low-Voltage Boost: ability to run the PA at full power even when the board’s supply dips near 3.3 V (via DC-DC), versus an LDO which cuts out below its dropout voltage.

  • Auto-switchover: the charger/regulator circuitry automatically selects USB or battery as needed.

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