The ESP32-C3 is a single-core RISC-V MCU with integrated 2.4 GHz WiFi (802.11b/g/n) and Bluetooth v5.0, targeting low-power IoT endpoints that need both protocols on one die (cites:,). On-chip memory totals 400kB SRAM and 384kB ROM, enough to run a lightweight RTOS with TCP/IP stack and BLE GATT server without external RAM (cites:).
Supply voltage is 3V to 3.6V (cites:) — a 3.3V rail with ±5% tolerance stays inside the window; a 3.0V LDO at end-of-life battery voltage still meets the minimum.
RF output, sensitivity, and current draw
Transmit power reaches 21dBm (cites:) at the antenna port, giving about +15 dBm EIRP with a 0 dBi chip antenna — enough for 100+ meter line-of-sight range in open air. Receiver sensitivity is -105dBm (cites:) for the 1 Mbps DSSS mode; real-world link budgets should subtract 3-5 dB for antenna mismatch and PCB loss. Current draw during transmission ranges from 276mA to 335mA (cites:), and receive current is 84mA to 87mA (cites:) — the delta matters for battery sizing when the device spends most time listening.
Espressif lists the ESP32-C3 as Active (cites:) — no end-of-life notice, no last-time buy trigger. New designs can commit without obsolescence risk.