STM32L432KBU 2.4GHz RF Dongle USB Type-C

An open-source, ultra-compact RF development dongle featuring an STM32L432KBU microcontroller paired with a Nordic Semiconductor nRF24L01 2.4GHz wireless transceiver and a USB-C port.

⚠️ Status: Work in Progress / Untested. This design is currently undergoing community review and has not yet been physically fabricated or validated on a test bench. Use at your own discretion.

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Design Previews

3D Render View

PCB Layout View

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Technical Specifications

Hardware Architecture

• MCU: STM32L432KBU6 (ARM Cortex-M4 @ 80MHz, 256KB Flash, 64KB SRAM)
• RF Transceiver: nRF24L01+ (2.4GHz ISM Band, GFSK modulation, up to 2Mbps data rate)
• Interface: Native USB 2.0 via a physical USB Type-C Connector
• Visual Diagnostics: * PA2 linked to Dedicated Hardware TX Status LED
  • PA3 linked to Dedicated Hardware RX Status LED
  • PA4 linked to General Purpose User LED

Mechanical Dimensions

• Width: 20 mm
• Length: 60 mm
• Form Factor: Slim USB-stick profile with an integrated PCB trace or edge-mounted antenna footprint.

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PCB Manufacturing & Layer Stackup

This board is designed strictly around the JLCPCB 4-Layer Controlled Impedance Stackup (JLC04161H-3313) using a standard 1.6mm total board thickness. This specific pre-preg and core arrangement is critical for maintaining correct 50Ω trace impedance matching for the 2.4GHz RF front-end.

Layer Structure

Layer	Type	Material	Thickness	Constant ($\epsilon_r$)
Top Layer	Signal / Copper	Copper (1 oz)	0.035 mm	—
Prepreg	Dielectric	7628*1	0.2104 mm	4.4
Internal Layer 2	Plane / GND	Copper (0.5 oz)	0.0175 mm	—
Core	Dielectric	Core	1.065 mm	4.5
Internal Layer 3	Signal / Power	Copper (0.5 oz)	0.0175 mm	—
Prepreg	Dielectric	7628*1	0.2104 mm	4.4
Bottom Layer	Signal / Copper	Copper (1 oz)	0.035 mm	—

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Repository Structure & Usage

This repository contains source design files only. To ensure workspace flexibility, components are cleanly bound directly inside the project archive.

• /Hardware
  • *.PrjPcb - Altium Project Binder
  • *.SchDoc - Schematic Sheets
  • *.PcbDoc - PCB Layout Geometry
  • *.SchLib & *.PcbLib - Complete component library assets including 3D STEP models.

How to Review

1. Clone this repository locally.
2. Open the .PrjPcb file inside Altium Designer.
3. Reviewers are encouraged to verify trace geometry tolerances, decoupling capacitor loops, and RF ground pour integrity before submitting feedback via GitHub Issues.

Keywords & Search Tags

STM32L432 Reference Design, nRF24L01 Schematic, USB-C Dongle Hardware, 4-Layer Controlled Impedance PCB, Altium RF Layout, JLC04161H-3313, 2.4GHz Antenna Breakout.