# Swiftlane SRB Lite Relay Board ## Description Swiftlane SRB Lite relay controller layout under production cleanup. Updated board-level rules to conservative manufacturable defaults (0.15 mm min trace and keep out, 0.25 mm board inset, explicit preferred widths) and audited remaining PCB blockers. Current blockers remain concentrated in overlapping copper, floating copper, and unrouted priority nets pending further interactive layout cleanup and re-route passes. ## Project Details - **Owner:** saurabhswiftlane - **Created:** 3/30/2026 - **Last Updated:** 4/8/2026 - **Visibility:** Public - **Manufacturer Part Number:** SRB-Lite-Concept-01 - **Manufacturer Name:** Swiftlane - **Connectivity:** RS-485 half-duplex with firmware update support - **Implementation Details:** 12V_AUX generated by LM5006 buck from RECTIFIED_DC. LM5006 FB reference is 2.5V, so R5=90.9k and R6=10k set VOUT to about 25.2V; current divider must be revised for a true 12V_AUX rail before production release. LD1117S33TR input should remain at or below 15V nominal. - **Operating Voltage:** 36V - **Max Current:** 0.5A - **Software:** Field firmware update uses STM32 system/bootloader-compatible RS-485 protocol via U2; factory programming and recovery use SWD on J4 - **Power Requirements:** 10-26VAC RMS or 10-36VDC input; 10VAC target minimum; 12VDC 500mA always-on output - **Part Type:** Relay Controller - **Stars:** 1 ## Key Components ### D1 — [CD-MMBL110S](https://www.flux.ai/jecstronic/cd-mmbl110s.md) - Forward Voltage: 900mV - Part Type: Bridge Rectifiers - Role Details: Rectifies 12-26VAC or 12-36VDC for internal power while strike path remains pre-bridge - Package: SMD - Role: Input Bridge Rectifier - Manufacturer Name: Bourns - Manufacturer Part Number: CD-MMBL110S - Datasheet URL: https://www.mouser.ca/datasheet/2/54/Bourns_CD_MMBL110S_datasheet-2586146.pdf **Pins:** - - - + - ~_1 - ~_2 ### D2 — [PMEG4010CEJ,115](https://www.flux.ai/jecstronic/pmeg4010cej115.md) - Manufacturer Name: Nexperia USA Inc. - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: Used for relay coil flyback and LM5006 bootstrap support - Role: Schottky Diode - Package: SOD-323 - Datasheet URL: https://www.mouser.com/datasheet/2/916/PMEG4010CEH_PMEG4010CEJ-2835951.pdf - Part Type: Diode - Manufacturer Part Number: PMEG4010CEJ,115 **Pins:** - A [pin 2] - K [pin 1] ### D3 — [PMEG4010CEJ,115](https://www.flux.ai/jecstronic/pmeg4010cej115.md) - Package: SOD-323 - Role Details: Used for relay coil flyback and LM5006 bootstrap support - Manufacturer Name: Nexperia USA Inc. - License: https://creativecommons.org/licenses/by/4.0/ - Role: Schottky Diode - Part Type: Diode - Datasheet URL: https://www.mouser.com/datasheet/2/916/PMEG4010CEH_PMEG4010CEJ-2835951.pdf - Manufacturer Part Number: PMEG4010CEJ,115 **Pins:** - A [pin 2] - K [pin 1] ### D4 — [PMEG4010CEJ,115](https://www.flux.ai/jecstronic/pmeg4010cej115.md) - Role Details: Used for relay coil flyback and LM5006 bootstrap support - Manufacturer Part Number: PMEG4010CEJ,115 - Role: Schottky Diode - Datasheet URL: https://www.mouser.com/datasheet/2/916/PMEG4010CEH_PMEG4010CEJ-2835951.pdf - Part Type: Diode - Manufacturer Name: Nexperia USA Inc. - Package: SOD-323 - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - A [pin 2] - K [pin 1] ### D5 — [SM712-02HTG](https://www.flux.ai/adrian95/sm712-02htg.md) - Part Type: Diodes - 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 - Manufacturer Part Number: SM712-02HTG - Package: SOT-23 - Role Details: Protects external A/B lines against ESD and surge transients - Manufacturer Name: Littelfuse - Mount: Surface Mount - Role: RS485 TVS - Package or Case Code: SOT-23 **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### D6 — [SMBJ36D-M3/H](https://www.flux.ai/adrian95/smbj36d-m3h.md) - Package: DO-214AA - Role Details: Clamps industrial input surges across 12-26VAC or 12-36VDC input - Manufacturer Name: Vishay General Semiconductor - Diodes Division - Role: Input TVS - Manufacturer Part Number: SMBJ36D-M3/H - Part Type: Diode - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.vishay.com/docs/87606/smbj5cdthrusmbj120cd.pdf **Pins:** - A [pin 2] - K [pin 1] ### F1 — [0ZCF0200AF2C](https://www.flux.ai/adrian95/0zcf0200af2c.md) - Datasheet URL: https://belfuse.com/resources/datasheets/circuitprotection/ds-cp-0zcf-series.pdf - Manufacturer Part Number: 0ZCF0200AF2C - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Fuse - Role: PTC Fuse - Manufacturer Name: BelFuse - Package or Case Code: FUSC7451X80N - Package: 1812 - Role Details: Series input overcurrent protection for board power path **Pins:** - ~ [pin 2] - ~ [pin 1] ### J1 — [DG250-3.5-02P-11-00A(H)](https://www.flux.ai/adrian95/dg250-3p5-02p-11-00ah.md) - Package: THT - Role: Input Power Terminal - Connector Positions: 2 - Part Type: Connector - Manufacturer Name: Degson - License: https://creativecommons.org/licenses/by/4.0/ - Pin Description: Pin 1=FIELD_IN_1, Pin 2=FIELD_IN_2 - Connector Type: Terminal Block - Role Details: Installer-facing field input terminal for 12-26VAC or 12-36VDC board power - Datasheet URL: https://www.tme.com/Document/74a50bb60bd70b3c953bc54e89073085/DG250-3.5.pdf - Manufacturer Part Number: DG250-3.5-02P-11-00A(H) **Pins:** - 1 [pin 1] - 2 [pin 2] ### J2 — [DG250-3.5-02P-11-00A(H)](https://www.flux.ai/adrian95/dg250-3p5-02p-11-00ah.md) - Connector Positions: 2 - Manufacturer Name: Degson - Part Type: Connector - Package: THT - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: Installer-facing RS-485 A/B communications terminal - Datasheet URL: https://www.tme.com/Document/74a50bb60bd70b3c953bc54e89073085/DG250-3.5.pdf - Pin Description: Pin 1=RS485_A, Pin 2=RS485_B - Role: RS-485 Terminal - Manufacturer Part Number: DG250-3.5-02P-11-00A(H) - Connector Type: Terminal Block **Pins:** - 1 [pin 1] - 2 [pin 2] ### J3 — [DG250-3.5-02P-11-00A(H)](https://www.flux.ai/adrian95/dg250-3p5-02p-11-00ah.md) - Role Details: Installer-facing switched auxiliary/strike output terminal - Package: THT - Manufacturer Part Number: DG250-3.5-02P-11-00A(H) - Datasheet URL: https://www.tme.com/Document/74a50bb60bd70b3c953bc54e89073085/DG250-3.5.pdf - Pin Description: Pin 1=STRIKE_NO_OUT, Pin 2=AUX_SW_OUT - Connector Type: Terminal Block - Role: Aux Output Terminal - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Connector - Connector Positions: 2 - Manufacturer Name: Degson **Pins:** - 1 [pin 1] - 2 [pin 2] ### J4 — [ARM JTAG SWD 10Pin 0.1" Connector](https://www.flux.ai/vasy_skral/arm-jtag-swd-10pin-01-connector.md) - Role: SWD Header - Part Type: Connector - Role Details: Provides SWD debug and recovery access alongside RS-485 firmware update support - Manufacturer Name: Wurth Elektronik - Datasheet URL: https://www.we-online.com/components/products/datasheet/61201021621.pdf - Package: THT - Pin Description: 1=VTref 3V3, 2=SWDIO, 3=GND, 4=SWCLK, 5=GND, 6=SWO, 10=NRST - Connector Positions: 10 - Connector Type: SWD Header - Manufacturer Part Number: 61201021621 **Pins:** - ~RESET~ [pin 10] - GND [pin 5] - GND [pin 3] - GNDDetect [pin 9] - NC [pin 7] - NC/TDI [pin 8] - SWDCLK/TCK [pin 4] - SWDIO/TMS [pin 2] - SWO/TDO [pin 6] - VTref [pin 1] ### J5 — [61300411121](https://www.flux.ai/adrian95/61300411121.md) - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.we-online.com/components/products/datasheet/61300411121.pdf - Manufacturer Name: Wurth Elektronik - Package or Case Code: HDRV4W95P0X254_1X4_1016X254X854P - Role Details: 1x4 UART/service header carrying 3V3, GND, RS485_TX, RS485_RX for direct bring-up and recovery - Role: Service Header - Part Type: Connector - Package: THT - Manufacturer Part Number: 61300411121 **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] ### K1 — [Relay-12VDC-SL-C](https://www.flux.ai/deadzerok/relay-12vdc-sl-c.md) - Part Type: Relay - Role: Power Relay - Manufacturer Name: Ningbo Songle Relay - Package: THT - Manufacturer Part Number: SRD-12VDC-SL-C - Datasheet URL: https://datasheet.lcsc.com/lcsc/2304140030_Ningbo-Songle-Relay-SRD-12VDC-SL-C_C30431.pdf - Implementation Details: NC contact is intentionally used as auxiliary switched output; relay symbol/library pin type should not be treated as no-connect for this design. - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: Form C relay for raw strike path switching ahead of the bridge rectifier; NC contact intentionally used for auxiliary switched output **Pins:** - Coil-1 [pin COIL1] - Coil-2 [pin COIL2] - Com-3 [pin COM] - NC [pin NC] - NO [pin NO] ### K2 — [Relay-12VDC-SL-C](https://www.flux.ai/deadzerok/relay-12vdc-sl-c.md) - Manufacturer Name: Ningbo Songle Relay - Implementation Details: NC contact is intentionally used as auxiliary switched output; relay symbol/library pin type should not be treated as no-connect for this design. - Role Details: Form C relay for raw strike path switching ahead of the bridge rectifier; NC contact intentionally used for auxiliary switched output - Part Type: Relay - Package: THT - Manufacturer Part Number: SRD-12VDC-SL-C - Datasheet URL: https://datasheet.lcsc.com/lcsc/2304140030_Ningbo-Songle-Relay-SRD-12VDC-SL-C_C30431.pdf - Role: Power Relay - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - Coil-1 [pin COIL1] - Coil-2 [pin COIL2] - Com-3 [pin COM] - NC [pin NC] - NO [pin NO] ### LED1 — [HSMA-C190](https://www.flux.ai/adrian95/hsma-c190.md) - Datasheet URL: https://docs.broadcom.com/docs/AV02-0112EN - Role: Relay Active LED - Manufacturer Part Number: HSMA-C190 - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: Dedicated relay activity LED; lights when either relay drive gate is asserted to aid installer diagnostics - Package: 0603 - Part Type: LED - Manufacturer Name: Broadcom Limited **Pins:** - A [pin 2] - K [pin 1] ### Q1 — [2N7002K](https://www.flux.ai/jecstronic/2n7002k.md) - Role Details: 3.3V GPIO-controlled low-side switch for 12V relay coil - Datasheet URL: https://www.infineon.com/dgdl/Infineon-2N7002-DS-v02_04-en.pdf - Manufacturer Name: MDD - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: 2N7002K - Part Type: Transistor - Role: Relay Driver MOSFET - Package: SOT-23 **Pins:** - D [pin 3] - G [pin 1] - S [pin 2] ### Q2 — [2N7002K](https://www.flux.ai/jecstronic/2n7002k.md) - Role Details: 3.3V GPIO-controlled low-side switch for 12V relay coil - License: https://creativecommons.org/licenses/by/4.0/ - Role: Relay Driver MOSFET - Manufacturer Name: MDD - Datasheet URL: https://www.infineon.com/dgdl/Infineon-2N7002-DS-v02_04-en.pdf - Manufacturer Part Number: 2N7002K - Package: SOT-23 - Part Type: Transistor **Pins:** - D [pin 3] - G [pin 1] - S [pin 2] ### U1 — [STM32F205RBT6](https://www.flux.ai/vasy_skral/stm32f205rbt6.md) - Datasheet URL: https://www.st.com/resource/en/datasheet/stm32f205vg.pdf - Manufacturer Name: STMicroelectronics - Role: Main MCU - Role Details: Manages RS-485 communications, firmware update path, relay timing, dry-contact monitoring, and supervisory logic - Manufacturer Part Number: STM32F205RBT6 - Software: Primary field update via RS-485 bootloader protocol; factory programming and recovery via SWD header J4 - Implementation Details: Datasheet-audited bring-up: all VDD pins tied to 3V3 with local decoupling; VDDA/VSSA tied to 3V3/GND with local 1uF + 10nF support; VBAT tied to 3V3 and decoupled when no backup source is used; VCAP1/VCAP2 each use 2.2uF ceramic capacitors with ESR below 2 ohms; BOOT0 defaults low for boot from user flash; PB2/BOOT1 held in defined state; NRST uses external pull-up and capacitor; SWD pins retained; no external HSE/LSE fitted so PH0/PH1 and PC14/PC15 reserved unless firmware later enables crystals; unused GPIO shall be configured as analog/no-pull in firmware at startup. - Package: LQFP-64 - Part Type: Microcontroller **Pins:** - BOOT0 [pin 60] - NRST [pin 7] - PA0 [pin 14] - PA1 [pin 15] - PA10 [pin 43] - PA11 [pin 44] - PA12 [pin 45] - PA13 [pin 46] - PA14 [pin 49] - PA15 [pin 50] - PA2 [pin 16] - PA3 [pin 17] - PA4 [pin 20] - PA5 [pin 21] - PA6 [pin 22] - PA7 [pin 23] - PA8 [pin 41] - PA9 [pin 42] - PB0 [pin 26] - PB1 [pin 27] - PB10 [pin 29] - PB11 [pin 30] - PB12 [pin 33] - PB13 [pin 34] - PB14 [pin 35] - PB15 [pin 36] - PB2 [pin 28] - PB3 [pin 55] - PB4 [pin 56] - PB5 [pin 57] - PB6 [pin 58] - PB7 [pin 59] - PB8 [pin 61] - PB9 [pin 62] - PC0 [pin 8] - PC1 [pin 9] - PC10 [pin 51] - PC11 [pin 52] - PC12 [pin 53] - PC13 [pin 2] - PC14 [pin 3] - PC15 [pin 4] - PC2 [pin 10] - PC3 [pin 11] - PC4 [pin 24] - PC5 [pin 25] - PC6 [pin 37] - PC7 [pin 38] - PC8 [pin 39] - PC9 [pin 40] - PD2 [pin 54] - PH0 [pin 5] - PH1 [pin 6] - VBAT [pin 1] - VCAP_1 [pin 31] - VCAP_2 [pin 47] - VDD [pin 64] - VDD [pin 48] - VDD [pin 19] - VDD [pin 32] - VDDA [pin 13] - VSS [pin 63] - VSS [pin 18] - VSSA [pin 12] ### U2 — [THVD1451D](https://www.flux.ai/kicad-part-library/thvd1451d.md) - Datasheet URL: http://www.ti.com/lit/ds/symlink/thvd1451.pdf - Manufacturer Name: Texas Instruments Inc. - Manufacturer Part Number: THVD1451D - Package or Case Code: SOIC-8_3.9x4.9mm_P1.27mm - Role: RS-485 Transceiver - Package: SOIC-8 - Role Details: UART-to-RS-485 physical layer for command/status traffic and bootloader firmware updates - Allow Substitutes: Yes **Pins:** - A [pin 8] - B [pin 7] - D [pin 3] - GND [pin 4] - R [pin 2] - VCC [pin 1] - Y [pin 5] - Z [pin 6] ### U3 — [LM5006MM](https://www.flux.ai/kicad-part-library/lm5006mm.md) - Manufacturer Part Number: LM5006MM - Role Details: Generates always-on 12V rail from rectified input with margin for 12VAC minimum operation - Datasheet URL: http://www.ti.com/lit/ds/symlink/lm5006.pdf - Package: MSOP-10 - Package or Case Code: MSOP-10_3x3mm_P0.5mm - Role: 12V Buck Regulator - Manufacturer Name: Texas Instruments Inc. - Allow Substitutes: Yes **Pins:** - BST [pin 2] - FB [pin 7] - LG [pin 3] - RT/SD [pin 8] - RTN [pin 4] - SW [pin 1] - UV [pin 5] - UVO [pin 6] - VCC [pin 9] - VIN [pin 10] ### U4 — [LD1117S33TR](https://www.flux.ai/adrian95/ld1117s33tr.md) - Role: 3.3V LDO - Package: SOT-223 - Allow Substitutes: Yes - Role Details: Generates MCU and transceiver logic rail from the 12V intermediate rail - Part Type: Integrated Circuit - Manufacturer Name: STMicroelectronics - Manufacturer Part Number: LD1117S33TR - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.st.com/content/ccc/resource/technical/document/datasheet/99/3b/7d/91/91/51/4b/be/CD00000544.pdf/files/CD00000544.pdf/jcr:content/translations/en.CD00000544.pdf **Pins:** - GND [pin 1] - IN [pin 3] - OUT [pin 2] - OUT [pin 4] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/saurabhswiftlane/swiftlane-srb-lite-relay-board](https://www.flux.ai/saurabhswiftlane/swiftlane-srb-lite-relay-board).* --- *Generated from [https://www.flux.ai/saurabhswiftlane/swiftlane-srb-lite-relay-board](https://www.flux.ai/saurabhswiftlane/swiftlane-srb-lite-relay-board)*