# Sarlls-IOT ## Description ESP32 Automotive High-Side Switch Board with 3G Connectivity and Robust 12V Protection ## Project Details - **Owner:** sarlls1 - **Created:** 10/14/2025 - **Last Updated:** 11/20/2025 - **Visibility:** Public - **System Architecture:** ```mermaid flowchart TD ESP32["ESP32 Module"] HS["High-Side Switch"] MOSFET["PFET"] Buck["Buck Converter"] Ind["Inductor"] Cout["Output Capacitor"] Rail3V3["3.3V Rail"] CANTrans["CAN Transceiver"] CANH["CAN_H"] CANL["CAN_L"] Term["120Ω Termination"] Modem3G["3G Modem"] GND["Ground"] HS --> MOSFET Buck --> Ind --> Cout --> Rail3V3 Buck --> GND Cout --> GND Ind --> GND ESP32 -->|Power| Rail3V3 ESP32 -->|GPIO| HS ESP32 -->|CAN| CANTrans CANTrans --> CANH CANTrans --> CANL CANH --> Term CANL --> Term ESP32 -->|UART| Modem3G ESP32 --> GND HS --> GND Buck --> GND CANTrans --> GND Modem3G --> GND ``` - **ERC/DRC Summary:** Latest ERC/DRC checks have been run in Flux. All schematic-level ERC issues related to ground unification, high-side switch topology, op-amp rails, 3.3V/EN RC network, buck converter passives, and CAN termination are resolved in the schematic. Layout-level DRC (including airwires between U7/C10/C16/C17/L4 and U4/R1) has been addressed at the netlist level; remaining layout issues, if any, are limited to physical routing/geometry (placement, copper, and trace shapes) which must be finalized manually in the PCB editor before fabrication. - **Power plane definition:** Inner layer 2 as ground plane; inner layer 3 as 12 V power plane - **PWR_HC netclass:** 2 oz copper high-current routing ## Key Components ### D1 — [SMBJ12A-13-F](https://www.flux.ai/lcsc/smbj12a-13-f~wkyd.md) - Role: Protection - Package or Case Code: SMB_L4.6-W3.6-LS5.3-RD - Manufacturer Name: DIODES(美台) - LCSC Part Number: C135038 - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2304140030_Diodes-Incorporated-SMBJ12A-13-F_C135038.pdf - Part Type: TVS - JLCPCB Part Class: Extended Part - Product Info Url: https://lcsc.com/product-detail/TVS_DIODES_SMBJ12A-13-F_SMBJ12A-13-F_C135038.html - Manufacturer Part Number: SMBJ12A-13-F - Role Details: TVS diode for 12 V front-end transient suppression **Pins:** - A [pin 2] - K [pin 1] ### D1 — [SPHV12-01ETG-C](https://www.flux.ai/adrian95/sphv12-01etg-c~ze3.md) - Manufacturer Name: Littelfuse Inc. - Manufacturer Part Number: SPHV12-01ETG-C - Datasheet URL: https://www.verical.com/datasheet/littelfuse-tvs-SPHV12-01ETG-C-895263.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Diode **Pins:** - A [pin 2] - C [pin 1] ### D2 — [SM6T12A](https://www.flux.ai/jecstronic/sm6t12a~mln.md) - Role Details: TVS diode for 12 V input net transient suppression - Part Type: Diode - Manufacturer Part Number: SM6T12A - Manufacturer Name: STMicroelectronics - Datasheet URL: https://www.mouser.com/datasheet/2/389/sm6t100a-1916590.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Package: DO-214AA - Role: Protection **Pins:** - A [pin 2] - K [pin 1] ### D3 — [SM8S12A](https://www.flux.ai/lcsc/sm8s12a~f2vq.md) - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2304140030_DOWO-SM8S12A_C314445.pdf - Manufacturer Part Number: SM8S12A - JLCPCB Part Class: Extended Part - Part Type: TVS - LCSC Part Number: C314445 - Manufacturer Name: DOWO(东沃) - Product Info Url: https://lcsc.com/product-detail/TVS_DOWO-SM8S12A_C314445.html - Role: Protection - Package or Case Code: DO-218AB_L13.5-W8.4-LS15.5-FD - Role Details: TVS diode for PROTECTED_12V_BUS transient suppression **Pins:** - A [pin 2] - K [pin 1] ### D4 — [NUP2105L](https://www.flux.ai/kicad-part-library/nup2105l~bk1.md) - Package or Case Code: SOT-23 - Datasheet URL: https://www.onsemi.com/pub_link/Collateral/NUP2105L-D.PDF - Manufacturer Part Number: NUP2105L - Role: Protection - Manufacturer Name: Texas Instruments Inc. - Role Details: ESD protection for CAN_H and CAN_L signal lines **Pins:** - A [pin 3] - K [pin 1] - K [pin 2] ### F1 — [1812L200/12DR](https://www.flux.ai/jecstronic/1812l20012dr~98l.md) - Manufacturer Part Number: 1812L150/12DR - Part Type: Fuse - License: https://creativecommons.org/licenses/by/4.0/ - Current Rating: 2A - Role: Protection - Role Details: Resettable fuse for 12 V automotive front-end current limiting - Datasheet URL: https://www.littelfuse.com/~/media/electronics/datasheets/resettable_ptcs/littelfuse_ptc_1812l_datasheet.pdf.pdf - Manufacturer Name: Littelfuse Inc. **Pins:** - P1 [pin 1] - P2 [pin 2] ### J1 — [2-Position Screw Terminal](https://www.flux.ai/corynrobinson/2-position-screw-terminal~s4.md) - Datasheet URL: https://www.we-online.com/katalog/datasheet/691137710002.pdf - Manufacturer Part Number: 691137710002 - Manufacturer Name: Würth Elektrik - Part Type: Connector - Role: Connector - Role Details: Power input connector for automotive 12V battery **Pins:** - P1 [pin 1] - P2 [pin 2] ### J2 — [DB9_Male_MountingHoles](https://www.flux.ai/robertdalesmith/db9malemountingholes~uz.md) - Datasheet URL: https://www.te.com/usa-en/product-2301843-2.datasheet.pdf - Role Details: Board-level CAN bus connector for external CAN_H and CAN_L - Purchase Url: https://www.digikey.com/en/products/detail/te-connectivity-amp-connectors/2301843-2/7776544 - Manufacturer Part Number: 2301843-2 - Manufacturer Name: TE Connectivity AMP Connectors - Part Type: Connector - Role: Connector **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] - 5 [pin 5] - 6 [pin 6] - 7 [pin 7] - 8 [pin 8] - 9 [pin 9] - PAD [pin 0] ### J3 — [U.FL-R-SMT-1(10)](https://www.flux.ai/jecstronic/upfl-r-smt-110~du.md) - Role: Connector - Datasheet URL: https://media.digikey.com/pdf/Data%20Sheets/Hirose%20PDFs/EDC3-302540-10.tif.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: 3G modem antenna connector for SIM800L ANT pin - Manufacturer Part Number: U.FL-R-SMT-1(10) - Part Type: Connector - Manufacturer Name: Hirose Electric Co Ltd **Pins:** - Center_Contact [pin 2] - Outer_Contact [pin 1] - Outer_Contact [pin 3] ### J4 — [USB Micro B](https://www.flux.ai/jharwinbarrozo/usb-micro-b~t8p.md) - Role: Connector - Manufacturer Part Number: 0473460001 - Manufacturer Name: Molex - Datasheet URL: https://www.molex.com/pdm_docs/sd/473460001_sd.pdf - Role Details: Programming port for ESP32 via USB-to-UART adapter - Part Type: USB B **Pins:** - D- [pin 2] - D+ [pin 3] - GND [pin 5] - ID [pin 4] - S1 [pin 6] - S2 [pin 7] - S3 [pin 8] - S4 [pin 9] - S5 [pin 10] - S6 [pin 11] - VBUS [pin 1] ### Q2 — [DMP3013SFV](https://www.flux.ai/kicad-part-library/dmp3013sfv~5bo.md) - Role: Switching - Role Details: High-side P-channel MOSFET for PROTECTED_12V_BUS, driven by U6 (LTC7001); intended as Q2 in the PFET high-side stage - Package or Case Code: Diodes_PowerDI3333-8 - Datasheet URL: https://www.diodes.com/assets/Datasheets/DMP3013SFV.pdf - Package: PowerDI3333-8 - Manufacturer Part Number: DMP3013SFV **Pins:** - D [pin 5] - G [pin 4] - S [pin 2] - S [pin 3] - S [pin 1] ### U1 — [ESP32-WROOM-32D](https://www.flux.ai/vasyl/esp32-wroom-32d~7py.md) - Datasheet URL: https://www.espressif.com/sites/default/files/documentation/esp32-wroom-32d_esp32-wroom-32u_datasheet_en.pdf - Role Details: Main MCU - Role: Processor - Part Type: Microcontroller - Manufacturer Name: Espressif Systems - Manufacturer Part Number: ESP32-WROOM-32D - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - 3.3V [pin 2] - AGND [pin 39] - CLK [pin 20] - CMD [pin 19] - EN [pin 3] - GND [pin 38] - GND [pin 15] - GND [pin 1] - IO0 [pin 25] - IO12 [pin 14] - IO13 [pin 16] - IO14 [pin 13] - IO15 [pin 23] - IO16 [pin 27] - IO17 [pin 28] - IO18 [pin 30] - IO19 [pin 31] - IO2 [pin 24] - IO21 [pin 33] - IO22 [pin 36] - IO23 [pin 37] - IO25 [pin 10] - IO26 [pin 11] - IO27 [pin 12] - IO32 [pin 8] - IO33 [pin 9] - IO34 [pin 6] - IO35 [pin 7] - IO4 [pin 26] - IO5 [pin 29] - NC [pin 32] - RXD0 [pin 34] - SD0 [pin 21] - SD1 [pin 22] - SD2 [pin 17] - SD3 [pin 18] - TXD0 [pin 35] - VN [pin 5] - VP [pin 4] ### U10 — [TPS7A7001DDA](https://www.flux.ai/kicad-part-library/tps7a7001dda~gu1.md) - Datasheet URL: http://www.ti.com/lit/ds/symlink/tps7a7001.pdf - Package or Case Code: TI_SO-PowerPAD-8 - Role Details: 4V LDO for SIM800L VBAT supply - Manufacturer Name: Texas Instruments Inc. - Role: Power Management - Manufacturer Part Number: TPS7A7001DDA - Package: TI_SO-PowerPAD-8 **Pins:** - EN [pin 2] - EP [pin 9] - FB [pin 7] - GND [pin 8] - IN [pin 3] - NC [pin 4] - NC [pin 5] - NC [pin 1] - OUT [pin 6] ### U2 — [TPD3E001DRLR](https://www.flux.ai/kicad-part-library/tpd3e001drlr~6l.md) - Manufacturer Name: Texas Instruments Inc. - Role Details: ESD protector for front-end IO/RF lines - Role: Protection - Datasheet URL: http://www.ti.com/lit/ds/symlink/tpd3e001.pdf - Package or Case Code: SOT-553 - Manufacturer Part Number: TPD3E001DRLR **Pins:** - ~ [pin 5] - ~ [pin 3] - IO1 [pin 1] - IO2 [pin 2] - IO3 [pin 4] ### U3 — [LM74800QDRRRQ1](https://www.flux.ai/jecstronic/lm74800qdrrrq1~l79.md) - Manufacturer Name: Texas Instruments - Role: Protection - Role Details: Reverse-polarity and ideal-diode controller for 12 V front-end - Datasheet URL: https://www.ti.com/lit/ds/symlink/lm7480-q1.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Integrated Circuit - Manufacturer Part Number: LM74800QDRRRQ1 **Pins:** - A [pin 2] - C [pin 12] - CAP [pin 11] - DGATE [pin 1] - DRR [pin 13] - EN/UVLO [pin 6] - GND [pin 7] - HGATE [pin 8] - OUT [pin 9] - OV [pin 5] - SW [pin 4] - VS [pin 10] - VSNS [pin 3] ### U4 — [SN65HVD230Q-Q1](https://www.flux.ai/adrian95/sn65hvd230q-q1~d7m.md) - Role Details: CAN transceiver for CAN_H and CAN_L - Manufacturer Part Number: SN65HVD230Q-Q1 - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Integrated Circuit - Manufacturer Name: Texas Instruments - Role: Interface - Datasheet URL: https://www.ti.com/lit/ds/symlink/sn65hvd230q-q1.pdf **Pins:** - CANH [pin 7] - CANL [pin 6] - D [pin 1] - GND [pin 2] - R [pin 4] - RS [pin 8] - VCC [pin 3] - VREF [pin 5] ### U5 — [LMV341QDBVRQ1](https://www.flux.ai/lcsc/lmv341qdbvrq1~xxfb.md) - Package or Case Code: SOT-23-6_L2.9-W1.6-P0.95-LS2.8-BR - Manufacturer Name: TI(德州仪器) - LCSC Part Number: C2058084 - JLCPCB Part Class: Extended Part - Role Details: Buffer and scale sensor input voltage to ADC, rail-to-rail input-range, automotive-grade - Role: Amplification - Manufacturer Part Number: LMV341QDBVRQ1 **Pins:** - ~{SHDN} [pin 5] - GND [pin 2] - IN- [pin 3] - IN+ [pin 1] - OUT [pin 4] - V+ [pin 6] ### U6 — [LTC7001IMSE#TRPBF](https://www.flux.ai/lcsc/ltc7001imsetrpbf~dfav.md) - Manufacturer Part Number: LTC7001IMSE#TRPBF - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2009180037_Analog-Devices-LTC7001IMSE-TRPBF_C690094.pdf - Role: Power Management - LCSC Part Number: C690094 - Package or Case Code: MSOP-10_L3.0-W3.0-P0.50-LS5.0-BL-EP - Role Details: Gate driver for high-side PFET switch - Manufacturer Name: ADI(亚德诺)/LINEAR(凌特) - Part Type: Gate Drive ICs - Product Info Url: https://lcsc.com/product-detail/Pre-ordered-Products_Analog-Devices_LTC7001IMSE-TRPBF_Analog-Devices-ADI-LINEAR-LTC7001IMSE-TRPBF_C690094.html - JLCPCB Part Class: Extended Part **Pins:** - BST [pin 9] - EP [pin 11] - GND [pin 3] - INP [pin 4] - NC [pin 10] - OVLO [pin 5] - TGDN [pin 6] - TGUP [pin 7] - TS [pin 8] - VCC [pin 1] - VCCUV [pin 2] ### U7 — [LM2596T-3.3/NOPB](https://www.flux.ai/jecstronic/lm2596t-3p3nopb~3yw.md) - Manufacturer Name: Texas Instruments - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: LM2596T-3.3/NOPB - Role Details: Buck converter regulator for 3.3V rail - Part Type: Integrated Circuit - Datasheet URL: https://www.ti.com/lit/ds/symlink/lm2596.pdf - Role: Power Management **Pins:** - ~ON~/OFF [pin 5] - FEED_BACK [pin 4] - GROUND [pin 3] - OUTPUT [pin 2] - VIN [pin 1] ### U8 — [SIM800L](https://www.flux.ai/lcsc/sim800l~c17y.md) - Manufacturer Part Number: SIM800L - Role Details: 3G cellular modem for UART interface to ESP32 - LCSC Part Number: C124276 - JLCPCB Part Class: Extended Part - Role: Connectivity - Part Type: 2G/3G/4G/5G Modules - Package or Case Code: GSMM-SMD_SIM800L - Manufacturer Name: SIMCOM(芯讯通无线科技) **Pins:** - ADC [pin 50] - ANT [pin 40] - BPI_BUS1 [pin 5] - COL0 [pin 20] - COL1 [pin 25] - COL2 [pin 22] - COL3 [pin 21] - COL4 [pin 24] - FM_ANT_N [pin 57] - FM_ANT_P [pin 17] - GND [pin 2] - GND [pin 6] - GND [pin 8] - GND [pin 35] - GND [pin 37] - GND [pin 38] - GND [pin 39] - GND [pin 41] - GND [pin 43] - GND [pin 44] - GND [pin 45] - GND [pin 58] - GND [pin 67] - GND [pin 71] - GND [pin 72] - GND [pin 73] - GND [pin 76] - GND [pin 77] - GND [pin 78] - GND [pin 79] - GND [pin 80] - GND [pin 81] - GND [pin 82] - GND [pin 83] - GND [pin 84] - GND [pin 85] - GND [pin 86] - GND [pin 87] - GND [pin 88] - GPIO1 [pin 3] - GPIO2 [pin 27] - GPIO3 [pin 28] - ISINK0 [pin 47] - ISINK1 [pin 46] - MIC1N [pin 12] - MIC1P [pin 52] - MIC2N [pin 10] - MIC2P [pin 9] - NC [pin 36] - NETLIGHT [pin 64] - PCMCLK [pin 29] - PCMIN [pin 66] - PCMOUT [pin 30] - PCMSYNC [pin 65] - PWM [pin 26] - PWRKEY [pin 48] - RESET [pin 49] - ROW0 [pin 62] - ROW1 [pin 60] - ROW2 [pin 61] - ROW3 [pin 23] - ROW4 [pin 63] - SCL [pin 74] - SDA [pin 75] - SIM_CLK [pin 55] - SIM_DATA [pin 14] - SIM_RST [pin 15] - SIMPRE [pin 54] - SPK1N [pin 13] - SPK1P [pin 53] - SPK2N [pin 11] - SPK2P8惟 [pin 51] - STATUS [pin 4] - UART_CTS [pin 34] - UART_DCD [pin 70] - UART_DTR [pin 69] - UART_RI [pin 68] - UART_RTS [pin 33] - UART_RXD [pin 31] - UART_TXD [pin 32] - USB_DM [pin 19] - USB_DP [pin 59] - VBAT [pin 1] - VBAT [pin 42] - VBUS [pin 7] - VEXT [pin 18] - VRTC [pin 56] - VSIM [pin 16] ### U9 — [TPS3839DBZ](https://www.flux.ai/kicad-part-library/tps3839dbz~y7.md) - Package or Case Code: SOT-23 - Role Details: Undervoltage supervisor for 3.3V rail - Package: SOT-23 - Manufacturer Name: Texas Instruments Inc. - Datasheet URL: http://www.ti.com/lit/ds/sbvs193d/sbvs193d.pdf - Manufacturer Part Number: TPS3839DBZ - Role: Power Management **Pins:** - ~{RESET} [pin 2] - GND [pin 1] - VDD [pin 3] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/sarlls1/sarlls-iot~9t](https://www.flux.ai/sarlls1/sarlls-iot~9t).* --- *Generated from [https://www.flux.ai/sarlls1/sarlls-iot~9t](https://www.flux.ai/sarlls1/sarlls-iot~9t)*