# USB Security Token ## Description This design implements a USB security token powered by an STM32 microcontroller. The device is engineered for compactness and efficient PCB integration while ensuring robust security features. Key elements of the design include: - **Microcontroller Core:** A STM32F103T8U6 serves as the primary processing unit, handling USB communication and security protocols. - **USB Interface:** A USB-A plug provides connectivity to the host. Dedicated net portals ensure proper routing of the VBUS, D+, D–, and ground signals. - **Power Regulation:** A low-dropout regulator supplies a stable 3.3V operating voltage, ensuring low noise and proper current supply to the microcontroller and peripherals. - **Signal Conditioning and EMI Filtering:** An EMI filter is used to maintain signal integrity and reduce interference while preserving the security token’s functionality. - **Synchronous Elements:** A ceramic resonator is incorporated to provide a precise clock source for USB data transfer and microcontroller operations. - **Additional Components:** Surface-mount resistors, capacitors, and LED indicators are deployed to ensure proper conditioning, decoupling, and status feedback. Their compact 0402 packages facilitate a highly integrated design. - **Connectivity and Net Portals:** Custom net portals are used throughout the schematic to streamline connectivity and PCB layout, keeping the design modular and easy to modify. This USB security token is designed with industry-standard components and robust connectivity to ensure secure, reliable operation in portable security applications. #USBToken #STM32 #PCBDesign #SecurityTechnology #PortableSecurity #Microcontrollers #USBInterface #PowerRegulation #EMIProtection #CompactDesign ## Project Details - **Owner:** jharwinbarrozo - **Created:** 3/1/2022 - **Last Updated:** 4/20/2026 - **Visibility:** Public - **Stars:** 29 - **Forks:** 42 - **Copies:** 34 ## Key Components ### J1 — [USB-A Plug PCB](https://www.flux.ai/jharwinbarrozo/usb-a-plug-pcb~6lp.md) - Part Type: USB A - Manufacturer Part Number: USB-A PCB Plug **Pins:** - D- [pin 2] - D+ [pin 3] - GND [pin 4] - VBUS [pin 1] ### J2 — [Connector-02x02-Counter-Clockwise](https://www.flux.ai/adrian95/97f3d650-165e-4674-0e89-02bf56318ff2~qxu.md) - Part Type: Connector **Pins:** - Pin_1 - Pin_2 - Pin_3 - Pin_4 ### LED1 — [LED 0603 (1608 Metric)](https://www.flux.ai/jharwinbarrozo/led-0603-1608-metric~yk.md) - Part Type: LED **Pins:** - A [pin 2] - K [pin 1] ### U1 — [ME6206A33XG](https://www.flux.ai/jharwinbarrozo/me6206a33xg~6u0.md) - Manufacturer Part Number: ME6206A33XG - Manufacturer Name: MICRONE - Part Type: Power Source - Datasheet URL: https://datasheet.lcsc.com/lcsc/1811101520_MICRONE-Nanjing-Micro-One-Elec-ME6206A33XG_C161345.pdf **Pins:** - GND - VI - VO ### U2 — [NUF2221W1T2G](https://www.flux.ai/jharwinbarrozo/nuf2221w1t2g~68.md) - Manufacturer Part Number: NUF2221W1T2G - Part Type: EMI Filter - Datasheet URL: https://www.onsemi.com/pdf/datasheet/nuf2221w1t2-d.pdf - Manufacturer Name: onsemi **Pins:** - D1c - D1i - D2c - D2i - GND - VDD ### U3 — [STM32F103T8U6](https://www.flux.ai/vasy_skral/stm32f103t8u6~e8m.md) - Manufacturer Name: STMicroelectronics - Datasheet URL: https://media.digikey.com/pdf/Data%20Sheets/ST%20Microelectronics%20PDFS/STM32F103x8,B.pdf - Manufacturer Part Number: STM32F103T8U6 - Part Type: Microcontroller **Pins:** - BOOT0 [pin 35] - NRST [pin 4] - PA0 [pin 7] - PA1 [pin 8] - PA10 [pin 22] - PA11 [pin 23] - PA12 [pin 24] - PA13 [pin 25] - PA14 [pin 28] - PA15 [pin 29] - PA2 [pin 9] - PA3 [pin 10] - PA4 [pin 11] - PA5 [pin 12] - PA6 [pin 13] - PA7 [pin 14] - PA8 [pin 20] - PA9 [pin 21] - PB0 [pin 15] - PB1 [pin 16] - PB2 [pin 17] - PB3 [pin 30] - PB4 [pin 31] - PB5 [pin 32] - PB6 [pin 33] - PB7 [pin 34] - PD0 [pin 2] - PD1 [pin 3] - VDD [pin 19] - VDD [pin 27] - VDD [pin 1] - VDDA [pin 6] - VSS [pin 37] - VSS [pin 26] - VSS [pin 18] - VSS [pin 36] - VSSA [pin 5] ### U4 — [HMX3033HNA](https://www.flux.ai/jharwinbarrozo/hmx3033hna~hxn.md) - Datasheet URL: https://datasheet.lcsc.com/lcsc/2007221833_AnaSem-HMX3033HNA_C697750.pdf - Manufacturer Name: Anasem - Manufacturer Part Number: HMX3033HNA - Part Type: Switch **Pins:** - VIN - VOUT - VSS ### Y1 — [CSTNE8M00G55A000R0](https://www.flux.ai/jharwinbarrozo/cstne8m00g55a000r0~ns.md) - Datasheet URL: https://datasheet.lcsc.com/lcsc/2008251032_Murata-Electronics-CSTNE8M00G55A000R0_C341523.pdf - Manufacturer Name: Murata Electronics - Manufacturer Part Number: CSTNE8M00G55A000R0 - Frequency: 8MHz **Pins:** - GND - OSC_IN - OSC_OUT *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/jharwinbarrozo/usb-security-token~4y5](https://www.flux.ai/jharwinbarrozo/usb-security-token~4y5).* --- *Generated from [https://www.flux.ai/jharwinbarrozo/usb-security-token~4y5](https://www.flux.ai/jharwinbarrozo/usb-security-token~4y5)*