# LTR-390UV-01 Reference Design ## Description This project is a design for a UV sensor circuit based on the Lite-On LTR-390UV-01. Key components include a voltage regulator (AP2112K-3.3TRG1), level-shifting N-channel MOSFETs (BSS138), resistors, and capacitors. The circuit interface includes I2C communication and power connections, facilitated through JST connectors. #referenceDesign #industrialsensing #liteon #template #reference-design ## Project Details - **Owner:** luc - **Created:** 6/17/2025 - **Last Updated:** 6/17/2025 - **Visibility:** Public - **License:** https://creativecommons.org/licenses/by/4.0/ ## Key Components ### J1 — [QWIIC I2C JST Connector](https://www.flux.ai/vasy_skral/qwiic-i2c-jst-connector~d55.md) - Manufacturer Part Number: SM04B-SRSS-TB - Manufacturer Name: JST Sales America Inc. - Part Type: Connector - Datasheet URL: https://media.digikey.com/pdf/Data%20Sheets/JST%20PDFs/SR%20Connector.pdf **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] ### J2 — [QWIIC I2C JST Connector](https://www.flux.ai/vasy_skral/qwiic-i2c-jst-connector~d55.md) - Datasheet URL: https://media.digikey.com/pdf/Data%20Sheets/JST%20PDFs/SR%20Connector.pdf - Part Type: Connector - Manufacturer Name: JST Sales America Inc. - Manufacturer Part Number: SM04B-SRSS-TB **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] ### Q1 — [BSS138](https://www.flux.ai/vasy_skral/bss138~3ld.md) - Datasheet URL: https://www.onsemi.com/pdf/datasheet/bss138-d.pdf - Manufacturer Part Number: BSS138 - Part Type: Transistor - Manufacturer Name: onsemi **Pins:** - D [pin 3] - G [pin 1] - S [pin 2] ### Q2 — [BSS138](https://www.flux.ai/vasy_skral/bss138~3ld.md) - Manufacturer Name: onsemi - Datasheet URL: https://www.onsemi.com/pdf/datasheet/bss138-d.pdf - Part Type: Transistor - Manufacturer Part Number: BSS138 **Pins:** - D [pin 3] - G [pin 1] - S [pin 2] ### U1 — [LTR-390UV-01](https://www.flux.ai/adrian95/ltr-390uv-01~7cf.md) - Manufacturer Name: Lite-On - Part Type: Sensor - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://optoelectronics.liteon.com/upload/download/DS86-2015-0004/LTR-390UV_Final_%20DS_V1%201.pdf - Manufacturer Part Number: LTR-390UV-01 **Pins:** - GND [pin 3] - INT [pin 5] - NC [pin 2] - SCL [pin 4] - SDA [pin 6] - VDD [pin 1] ### U2 — [AP2112K-3.3TRG1](https://www.flux.ai/adrian95/ap2112k-33trg1~zlq.md) - Datasheet URL: Diodes Incorporated - Manufacturer Part Number: AP2112K-3.3TRG1 - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Integrated Circuit - Manufacturer Name: https://www.diodes.com/assets/Datasheets/AP2112.pdf **Pins:** - EN [pin 3] - GND [pin 2] - NC [pin 4] - VIN [pin 1] - VOUT [pin 5] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/luc/ltr-390uv-01-reference-design~ha](https://www.flux.ai/luc/ltr-390uv-01-reference-design~ha).* --- *Generated from [https://www.flux.ai/luc/ltr-390uv-01-reference-design~ha](https://www.flux.ai/luc/ltr-390uv-01-reference-design~ha)*