KAGA FEI ES4L15BA1 is an ultra-small Bluetooth LE 6.0 and 802.15.4 module based on Nordic nRF54L15 SoC

Japanese company KAGA FEI has recently unveiled the incredibly small ES5L15BA1 Bluetooth LE 6.0 and 802.15.4 module based on Nordic Semi nRF54L15 ultra-low-power Cortex-M33 wireless MCU.

We had previously covered the u-Blox NORA-B2 which I already found pretty small at 14.3 x 10.4 x 1.9mm, but the ES5L15BA1 module goes a step further measuring just 8.55 x 3.25 x 1.00 mm with an integrated antenna which could make it the world’s smallest Bluetooth LE module.

KAGA FEI ES4L15BA1 specifications:

SoC – Nordic Semiconductor nRF54L15
- MCU cores
  - Arm Cortex-M33 with Arm TrustZone @ 128MHz
  - RISC-V coprocessor for software-defined peripheral
- Memory – 256KB SRAM
- Storage – 1.5MB non-volatile memory
- Wireless
  - Bluetooth 6.0
    - Data rates – 2Mbps, 1Mbps, 500kbps, 125kbps
    - Features
      - AoA / AoD
      - Channel Sounding
  - 802.15.4 radio for Thread / Zigbee / Matter
  - Nordic Proprietary 2.4 GHz protocol up to 4 Mbps
  - Frequency – 2402 to 2480 MHz
  - +8dBm output power
Antenna – Integrated high-performance PCB antenna
Peripherals
- 14x GPIO pads
- Software-defined peripheral enabled by the RISC-V core
- 14-bit ADC
- Global RTC
Security
- Arm TrustZone-M
- Designed for PSA Certified Level 3 IoT security standard
Power Supply – 1.7V to 3.6V
Dimensions – 8.55 x 3.25 x 1.00 mm
Temperature Range – -40°C to 105°C
Certifications
- Radio Law MIC (Japan), FCC (USA), ISED (Canada) qualification
- ETSI EN 300 328 v2.2.2 Conducted Test Report Available
- RoHS compliant / Complete Lead-Free

We don’t have much information about firmware/software, but it’s most probably just going to rely on Nordic Sermi nRF Connect SDK like other Nordic modules. It will implement the latest features found in Bluetooth 6.0 such as channel sounding for accurate distance measurement. Its tiny size and low power consumption mean it is suitable for small medical/healthcare products and wearable devices that require a compact form factor. The ES4L15BA1-EVB evaluation board and ES4L15BA1-EVK evaluation kit are also in the works, but we have no specific details about these at this stage.

Considering the nRF54L15 microcontroller itself is not in mass production yet, you’ll need to wait for a bit longer because getting your hands on the ultra-small ES5L15BA1 Bluetooth LE 6.0 and 802.15.4 module. KAGA FEI expects sampling to start in February 2025 and mass production in 2025. Additional information may be found on the product page and the press release.

Thanks to TLS for the tip.

Jean-Luc Aufranc (CNXSoft)

Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.