ELPM-S3LW
Extreme low-power module
Datasheet
CAD files
01 · Specifications
Every figure here is printed in the datasheet.
The ELPM-S3LW is an extreme low-power module based on the ESP32-S3FN8 and the SX1262, made for battery-powered and energy-harvesting IoT devices. Its power unit adapts to each use case and, with Deep Stop mode, brings consumption down to a minimum, an ATECC608C crypto element covers the security side.
Core
| Microcontroller | ESP32-S3FN8 (32-bit 240 MHz) |
|---|---|
| Flash | 8 MB |
| PSRAM | External PSRAM can be installed |
| WiFi | IEEE 802.11 b/g/n |
| Bluetooth LE | Bluetooth 5, Bluetooth mesh |
| Interfaces | I²C, I²S, SPI, UART, USB |
| Security | Cryptographic hardware acceleration |
| External RTC | RV-3028-C7 (45–100 nA) |
| Status LED | RGB WS2812B on GPIO48 |
| I²C pull-ups | Integrated, SDA GPIO8 and SCL GPIO9 |
Sub-GHz
| Transceiver | SX1262 |
|---|---|
| Frequency bands | 862 MHz to 928 MHz |
| Signal power | 22 dBm |
| Air data rate | 0.3 kbps to 62.5 kbps |
| Dissipation power | 1 W |
| Interface | SPI |
| Supply | Dedicated LDO2 3.3 V @ 300 mA |
| Antenna | 50 Ω U.FL / pad |
| Compatibility | LoRa and LoRaWAN |
Mechanical & certification
| Dimensions | 30 × 18 × 2.83 mm |
|---|---|
| Weight | 2.29 g |
| Certification | Pending release of the ELPM-S3LW version for mass production. |
Power traces · Otii
The bench recordings behind these numbers.
02 · Why ELPM-S3LW
Built so the idle state costs nothing.
A 30 × 18 mm module pairing an ESP32-S3FN8 with an SX1262 LoRa transceiver. A hardware power latch cuts the module down to a deep stop measured below one nanoamp, so a battery-powered node can wait years between transmissions.
Hardware power latch
A master latch with gate, wake and force-on inputs physically removes power instead of idling the CPU. Deep stop is specified below 1 nA with the RTC disabled.
Extreme low-power RTC
An external RV-3028-C7 draws 45–100 nA and provides multiple interrupt sources, so a scheduled wake-up does not require keeping the SoC alive.
Two radios, two bands
SX1262 for LoRa and LoRaWAN on the sub-GHz bands, plus the ESP32-S3 radio for WiFi 802.11 b/g/n and Bluetooth 5 with mesh.
Separated power paths
Dedicated LDOs for the SoC and for the LoRa section, a dedicated RTC supply pad, and a battery-level circuit with zero leakage current.
Edge-detecting inputs
A rising/falling edge detector and wake/gate inputs operate in the 1–30 nA range, so an external event can start the module from deep stop.
Castellated and solderable
61 castellated holes plus 8 ground pads on a 30 × 18 mm outline, with I²C, I²S, SPI, UART and USB brought out.
Typical applications
Where a nanoamp makes the difference.
Wireless sensor networks
Battery nodes that report for years, deep stop between transmissions and LoRa for the distance.
Asset tracking
Wakes on movement or on schedule, transmits, goes back below a nanoamp.
Industrial IoT
Sub-GHz reach plus local WiFi/BLE,
with a −40 to +85 °C operating range.
Security & monitoring
Edge-detecting inputs start the module from deep stop on an external event.
FAQ
Questions, answered.
Is it certified?
Not yet. The units in circulation are engineering samples with no CE or FCC marking, and certification is tied to the release of the mass-production version. Use them for evaluation, prototyping and integration testing, not inside a product placed on the market.
Can I buy it right now?
Direct sales are suspended. Engineering samples and volume quotes go through info@objexlabs.com, and in the meantime the datasheet and the CAD sources at the top of the page are enough to freeze the footprint and start the integration.
Is it LoRaWAN compatible?
Yes. The SX1262 covers LoRa and LoRaWAN from 862 to 928 MHz, up to 22 dBm, with an air data rate between 0.3 and 62.5 kbps. It hangs off the ESP32-S3 over SPI and runs on its own LDO2 rail (3.3 V, 300 mA), and the RF path ends on a 50 Ω U.FL connector or on the antenna pad. The stack is your choice, any LoRaWAN library with an SX126x driver works.
How do I program it?
It behaves like any 240 MHz ESP32-S3 with 8 MB of flash, so ESP-IDF, PlatformIO, the Arduino core and MicroPython all work. Flashing goes over native USB or UART. USB, UART, SPI, I²C and I²S come out on the castellated holes, the I²C pull-ups are already on board (SDA on GPIO8, SCL on GPIO9) and the RGB WS2812B status LED sits on GPIO48.
What does a sub-nanoamp deep stop actually mean?
That what is left is leakage current, not sleep current. The power latch, with its gate, wake and force-on inputs, physically opens the supply rails instead of putting the SoC into deep sleep, so with the RTC disabled the module draws less than 1 nA. Wake-up comes from a rising or falling edge on the detector inputs, which operate between 1 and 30 nA, or on schedule from the RV-3028-C7 RTC (45–100 nA). Against the tens of microamps of a conventional deep sleep, the energy budget of a node that transmits a few times a day changes by orders of magnitude.
