# CSMA CD RS485 to RS232 Converter ## Description Welcome to your new project. Imagine what you can build here. ## Project Details - **Owner:** paulkbrown - **Created:** 4/19/2026 - **Last Updated:** 4/22/2026 - **Visibility:** Public ## Key Components ### D1 — [SM712-02HTG](https://www.flux.ai/adrian95/sm712-02htg~cby.md) - Package or Case Code: SOT-23 - Manufacturer Part Number: SM712-02HTG - Package: SOT-23-3 - Part Type: Diodes - Mount: Surface Mount - Manufacturer Name: Littelfuse - Role Details: Dedicated RS-485 line protection placed at the bus connector - Role: RS-485 TVS Protection - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.littelfuse.com/media?resourcetype=datasheets&itemid=a4019802-ff62-41ff-bf66-295f97422f81&filename=littelfuse-tvs-diode-array-sm712-datasheet **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### D2 — [PMEG2010AET](https://www.flux.ai/kicad-part-library/pmeg2010aet~c8.md) - Role: Reverse Polarity Protection - Package: SOT-23 - Datasheet URL: https://assets.nexperia.com/documents/data-sheet/PMEG2010AEH_PMEG2010AET.pdf - Role Details: Series Schottky diode for simple reverse polarity protection on the input supply - Package or Case Code: SOT-23 - Manufacturer Part Number: PMEG2010AET - Manufacturer Name: Texas Instruments Inc. **Pins:** - A [pin 1] - K [pin 3] - NC [pin 2] ### D3 — [SZSMF5.0AT1G](https://www.flux.ai/adrian95/szsmf5p0at1g~1jh.md) - Manufacturer Name: Littelfuse Inc. - Manufacturer Part Number: SZSMF5.0AT1G - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: TVS diode across input supply after connector for transient suppression - Role: Input TVS Protection - Package: SOD-123FL - Part Type: Diode - Datasheet URL: https://www.mouser.com/datasheet/2/240/Littelfuse_TVS_Diode_SZSMFxxA_Datasheet_pdf-1634909.pdf **Pins:** - A [pin 2] - C [pin 1] ### F1 — [MF-R050-2](https://www.flux.ai/adrian95/mf-r050-2~y77.md) - Role: Input Overcurrent Protection - Part Type: Fuse - Role Details: Resettable fuse to limit sustained input fault current - Manufacturer Part Number: MF-R050-2 - Package: Radial - Datasheet URL: https://www.bourns.com/docs/product-datasheets/mf-r.pdf - Manufacturer Name: Bourns Inc. - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - 1 [pin 1] - 2 [pin 2] ### J1 — [282837-3](https://www.flux.ai/adrian95/282837-3~5mc.md) - Role: Power Input Connector - License: https://creativecommons.org/licenses/by/4.0/ - Package: Through Hole - Manufacturer Name: TE Connectivity AMP Connectors - Part Type: Connector - Manufacturer Part Number: 282837-3 - Role Details: 3-position input connector for VIN, GND, and optional spare pin - Datasheet URL: https://www.te.com/usa-en/product-282837-3.datasheet.pdf **Pins:** - Pin_1 [pin 1] - Pin_2 [pin 2] - Pin_3 [pin 3] ### J2 — [282837-3](https://www.flux.ai/adrian95/282837-3~5mc.md) - License: https://creativecommons.org/licenses/by/4.0/ - Package: Through Hole - Manufacturer Name: TE Connectivity AMP Connectors - Part Type: Connector - Manufacturer Part Number: 282837-3 - Role: RS-485 Connector - Role Details: 3-position field connector for A, B, and GND - Datasheet URL: https://www.te.com/usa-en/product-282837-3.datasheet.pdf **Pins:** - Pin_1 [pin 1] - Pin_2 [pin 2] - Pin_3 [pin 3] ### J3 — [282834-5](https://www.flux.ai/adrian95/282834-5~6mp.md) - Role Details: 5-position terminal strip replacing the previous J3 connector for RS-232 and auxiliary I/O wiring - Package: Through Hole - Manufacturer Part Number: 282834-5 - Role: RS-232 terminal strip - Datasheet URL: https://www.te.com/usa-en/product-282834-5.datasheet.pdf - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: TE Connectivity AMP Connectors **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] - 5 [pin 5] ### U1 — [LTC1482CS8#TRPBF](https://www.flux.ai/lcsc/ltc1482cs8trpbf~3tvd.md) - Manufacturer Name: ADI(亚德诺)/LINEAR - Package or Case Code: SO-8_L4.9-W3.9-P1.27-LS6.0-BL - Role Details: LTC1482 family half-duplex transceiver, using closest library variant to requested LTC1482CSB - Package: SO-8 - LCSC Part Number: C675698 - Role: RS-485 Transceiver - Manufacturer Part Number: LTC1482CS8#TRPBF **Pins:** - ~{CD} [pin 2] - A [pin 6] - B [pin 7] - DE [pin 3] - DI/~{SHDN} [pin 4] - GND [pin 5] - RO [pin 1] - VCC [pin 8] ### U2 — [MAX232EIN](https://www.flux.ai/lcsc/max232ein~eg50.md) - JLCPCB Part Class: Extended Part - Part Type: RS232 ICs - Role Details: Generates and receives RS-232 signal levels from the internal 5 V logic domain - Package or Case Code: PDIP-16_L19.7-W6.6-P2.54-LS7.6-BL - Role: RS-232 Transceiver - LCSC Part Number: C2860250 - Package: PDIP-16 - Manufacturer Name: TI(德州仪器) - Manufacturer Part Number: MAX232EIN **Pins:** - C1+ [pin 1] - C1− [pin 3] - C2+ [pin 4] - C2− [pin 5] - DIN1 [pin 11] - DIN2 [pin 10] - DOUT1 [pin 14] - DOUT2 [pin 7] - GND [pin 15] - RIN1 [pin 13] - RIN2 [pin 8] - ROUT1 [pin 12] - ROUT2 [pin 9] - VCC [pin 16] - VS+ [pin 2] - VS− [pin 6] ### U3 — [SN74LVC1G04DCKR](https://www.flux.ai/vasy_skral/sn74lvc1g04dckr~6e.md) - Datasheet URL: https://www.ti.com/lit/ds/symlink/sn74lvc1g04.pdf - Role Details: Single inverter used to create inverted DE control from MAX232 R2OUT - Manufacturer Part Number: SN74LVC1G04DCKR - Role: Logic Inverter - Manufacturer Name: Texas Instruments - Part Type: Integrated Circuit - Package: SC-70-5 **Pins:** - A [pin 2] - GND [pin 3] - NC [pin 1] - VCC [pin 5] - Y [pin 4] ### U4 — [SK78L05](https://www.flux.ai/lcsc/sk78l05~wly.md) - Role: 5 V Linear Regulator - Manufacturer Name: suntek(洺太电子) - LCSC Part Number: C2986183 - Role Details: 78L05-family regulator used as library fallback for requested AS78L05RTR-E1DICT-ND - Package: SOT-89-3 - Part Type: Linear Voltage Regulators (LDO) - JLCPCB Part Class: Extended Part - Manufacturer Part Number: SK78L05 - Package or Case Code: SOT-89-3_L4.5-W2.5-P1.50-LS4.1-BR **Pins:** - GND [pin 2] - VIN [pin 3] - VOUT [pin 1] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/paulkbrown/csma-cd-rs485-to-rs232-converter~47](https://www.flux.ai/paulkbrown/csma-cd-rs485-to-rs232-converter~47).* --- *Generated from [https://www.flux.ai/paulkbrown/csma-cd-rs485-to-rs232-converter~47](https://www.flux.ai/paulkbrown/csma-cd-rs485-to-rs232-converter~47)*