# Dual PCA9685 Servo Controller ## Description 4-layer dual PCA9685 servo controller with Raspberry Pi 5, STM32 Nucleo, TXS0102 I2C level shifting, 6.0V/20A servo rail, and 5.1V logic rail. ## Project Details - **Owner:** deff4rk3 - **Created:** 5/6/2026 - **Last Updated:** 5/6/2026 - **Visibility:** Public - **Implementation Details:** PCB configured as 4-layer: Top signal, Layer 2 continuous GND plane, Layer 3 split power plane for 5.1V logic and 6.0V servo distribution, Bottom signal. Fabrication requirement: 2 oz copper for high-current 6.0V servo rail and wide copper pours/planes for 20A load support. ## Key Components ### J1 — [D2540-6002-AR](https://www.flux.ai/adrian95/d2540-6002-ar~sw.md) - Connector Gender: Male - Connector Rows: 2 - Datasheet URL: http://multimedia.3m.com/mws/media/485877O/3m-four-wall-header-d2500-series-ts-2244.pdf - Connector Type: Headers and Wire Housings - Manufacturer Part Number: D2540-6002-AR - Part Type: Connector - Manufacturer Name: 3M - Connector Positions: 40 - License: https://creativecommons.org/licenses/by/4.0/ - Package or Case Code: SHDR40W64P254_2X20_5812X859X991P - Connector Pitch: 2.54mm **Pins:** - 1 [pin 1] - 10 [pin 10] - 11 [pin 11] - 12 [pin 12] - 13 [pin 13] - 14 [pin 14] - 15 [pin 15] - 16 [pin 16] - 17 [pin 17] - 18 [pin 18] - 19 [pin 19] - 2 [pin 2] - 20 [pin 20] - 21 [pin 21] - 22 [pin 22] - 23 [pin 23] - 24 [pin 24] - 25 [pin 25] - 26 [pin 26] - 27 [pin 27] - 28 [pin 28] - 29 [pin 29] - 3 [pin 3] - 30 [pin 30] - 31 [pin 31] - 32 [pin 32] - 33 [pin 33] - 34 [pin 34] - 35 [pin 35] - 36 [pin 36] - 37 [pin 37] - 38 [pin 38] - 39 [pin 39] - 4 [pin 4] - 40 [pin 40] - 5 [pin 5] - 6 [pin 6] - 7 [pin 7] - 8 [pin 8] - 9 [pin 9] ### J10 — [22-28-4033](https://www.flux.ai/adrian95/22-28-4033~4k2.md) - Datasheet URL: https://www.molex.com/pdm_docs/sd/022284033_sd.pdf - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: 0022284033 - Connector Pitch: 2.54mm - Connector Type: Headers and Wire Housings - Connector Gender: Male - Connector Rows: 1 - Manufacturer Name: Molex - Connector Positions: 3 **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J11 — [22-28-4033](https://www.flux.ai/adrian95/22-28-4033~4k2.md) - Connector Rows: 1 - Manufacturer Name: Molex - Connector Positions: 3 - Connector Pitch: 2.54mm - Connector Type: Headers and Wire Housings - Connector Gender: Male - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: 0022284033 - Datasheet URL: https://www.molex.com/pdm_docs/sd/022284033_sd.pdf **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J12 — [22-28-4033](https://www.flux.ai/adrian95/22-28-4033~4k2.md) - Datasheet URL: https://www.molex.com/pdm_docs/sd/022284033_sd.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Connector - Manufacturer Part Number: 0022284033 - Connector Pitch: 2.54mm - Connector Gender: Male - Connector Type: Headers and Wire Housings - Connector Rows: 1 - Connector Positions: 3 - Manufacturer Name: Molex **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J13 — [22-28-4033](https://www.flux.ai/adrian95/22-28-4033~4k2.md) - Manufacturer Part Number: 0022284033 - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.molex.com/pdm_docs/sd/022284033_sd.pdf - Manufacturer Name: Molex - Connector Positions: 3 - Connector Rows: 1 - Connector Type: Headers and Wire Housings - Connector Gender: Male - Connector Pitch: 2.54mm **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J14 — [22-28-4033](https://www.flux.ai/adrian95/22-28-4033~4k2.md) - Datasheet URL: https://www.molex.com/pdm_docs/sd/022284033_sd.pdf - Manufacturer Part Number: 0022284033 - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Connector Type: Headers and Wire Housings - Connector Gender: Male - Connector Pitch: 2.54mm - Manufacturer Name: Molex - Connector Positions: 3 - Connector Rows: 1 **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J15 — [22-28-4033](https://www.flux.ai/adrian95/22-28-4033~4k2.md) - Datasheet URL: https://www.molex.com/pdm_docs/sd/022284033_sd.pdf - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: 0022284033 - Connector Pitch: 2.54mm - Connector Type: Headers and Wire Housings - Connector Gender: Male - Connector Rows: 1 - Manufacturer Name: Molex - Connector Positions: 3 **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J16 — [22-28-4033](https://www.flux.ai/adrian95/22-28-4033~4k2.md) - Manufacturer Part Number: 0022284033 - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Connector - Datasheet URL: https://www.molex.com/pdm_docs/sd/022284033_sd.pdf - Manufacturer Name: Molex - Connector Positions: 3 - Connector Rows: 1 - Connector Gender: Male - Connector Type: Headers and Wire Housings - Connector Pitch: 2.54mm **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J17 — [22-28-4033](https://www.flux.ai/adrian95/22-28-4033~4k2.md) - Connector Gender: Male - Connector Type: Headers and Wire Housings - Connector Pitch: 2.54mm - Manufacturer Name: Molex - Connector Positions: 3 - Connector Rows: 1 - Datasheet URL: https://www.molex.com/pdm_docs/sd/022284033_sd.pdf - Manufacturer Part Number: 0022284033 - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Connector **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J18 — [22-28-4033](https://www.flux.ai/adrian95/22-28-4033~4k2.md) - Connector Gender: Male - Connector Type: Headers and Wire Housings - Connector Pitch: 2.54mm - Connector Positions: 3 - Manufacturer Name: Molex - Connector Rows: 1 - Datasheet URL: https://www.molex.com/pdm_docs/sd/022284033_sd.pdf - Manufacturer Part Number: 0022284033 - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Connector **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J19 — [22-28-4033](https://www.flux.ai/adrian95/22-28-4033~4k2.md) - Connector Pitch: 2.54mm - Connector Type: Headers and Wire Housings - Connector Gender: Male - Connector Rows: 1 - Connector Positions: 3 - Manufacturer Name: Molex - Datasheet URL: https://www.molex.com/pdm_docs/sd/022284033_sd.pdf - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: 0022284033 **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J2 — [Pin Header 02x08 2.54mm Vertical](https://www.flux.ai/adrian95/pin-header-02x08-254mm-vertical~7de.md) - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - Pin_1 [pin 1] - Pin_10 [pin 10] - Pin_11 [pin 11] - Pin_12 [pin 12] - Pin_13 [pin 13] - Pin_14 [pin 14] - Pin_15 [pin 15] - Pin_16 [pin 16] - Pin_2 [pin 2] - Pin_3 [pin 3] - Pin_4 [pin 4] - Pin_5 [pin 5] - Pin_6 [pin 6] - Pin_7 [pin 7] - Pin_8 [pin 8] - Pin_9 [pin 9] ### J20 — [TE-1986242-2](https://www.flux.ai/tbjers/te-1986242-2~0v.md) - Role: High Current Power Input - Connector Pitch: 15mm - Datasheet URL: https://www.te.com/commerce/DocumentDelivery/DDEController?Action=srchrtrv&DocNm=9-1773451-7_HIGH_POWER_TERMINAL_BLOCKS&DocType=Data%20Sheet&DocLang=English&PartCntxt=1986242-2&DocFormat=pdf - Role Details: 6.0V servo rail input, specified for 20A load support; place near servo connector bank and route with 2 oz copper pours/planes - Manufacturer Part Number: 1986242-2 - Current Rating: 125A - Manufacturer Name: TE Connectivity - Voltage Rating: 600V **Pins:** - A1 - A2 - A3 - A4 - B1 - B2 - B3 - B4 ### J21 — [282837-2](https://www.flux.ai/vasy_skral/282837-2~69k.md) - Role Details: 5.1V logic rail input for PCA9685 VDD and TXS0102 VCCB - Part Type: Connector - Datasheet URL: https://www.te.com/commerce/DocumentDelivery/DDEController?Action=srchrtrv&DocNm=282837&DocType=Customer+Drawing&DocLang=English - Symbol Style: parametric-v1 - Manufacturer Name: TE Connectivity AMP Connectors - Role: Logic Power Input - Manufacturer Part Number: 282837-2 **Pins:** - 1 [pin 1] - 2 [pin 2] ### J3 — [22-28-4033](https://www.flux.ai/adrian95/22-28-4033~4k2.md) - Manufacturer Part Number: 0022284033 - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Connector - Datasheet URL: https://www.molex.com/pdm_docs/sd/022284033_sd.pdf - Connector Positions: 3 - Manufacturer Name: Molex - Connector Rows: 1 - Connector Gender: Male - Connector Type: Headers and Wire Housings - Connector Pitch: 2.54mm **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J4 — [22-28-4033](https://www.flux.ai/adrian95/22-28-4033~4k2.md) - Connector Pitch: 2.54mm - Connector Gender: Male - Connector Type: Headers and Wire Housings - Connector Rows: 1 - Manufacturer Name: Molex - Connector Positions: 3 - Datasheet URL: https://www.molex.com/pdm_docs/sd/022284033_sd.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Connector - Manufacturer Part Number: 0022284033 **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J5 — [22-28-4033](https://www.flux.ai/adrian95/22-28-4033~4k2.md) - Manufacturer Part Number: 0022284033 - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.molex.com/pdm_docs/sd/022284033_sd.pdf - Manufacturer Name: Molex - Connector Positions: 3 - Connector Rows: 1 - Connector Type: Headers and Wire Housings - Connector Gender: Male - Connector Pitch: 2.54mm **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J6 — [22-28-4033](https://www.flux.ai/adrian95/22-28-4033~4k2.md) - Manufacturer Part Number: 0022284033 - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.molex.com/pdm_docs/sd/022284033_sd.pdf - Connector Positions: 3 - Manufacturer Name: Molex - Connector Rows: 1 - Connector Type: Headers and Wire Housings - Connector Gender: Male - Connector Pitch: 2.54mm **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J7 — [22-28-4033](https://www.flux.ai/adrian95/22-28-4033~4k2.md) - Connector Rows: 1 - Manufacturer Name: Molex - Connector Positions: 3 - Connector Pitch: 2.54mm - Connector Type: Headers and Wire Housings - Connector Gender: Male - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: 0022284033 - Datasheet URL: https://www.molex.com/pdm_docs/sd/022284033_sd.pdf **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J8 — [22-28-4033](https://www.flux.ai/adrian95/22-28-4033~4k2.md) - Manufacturer Part Number: 0022284033 - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.molex.com/pdm_docs/sd/022284033_sd.pdf - Manufacturer Name: Molex - Connector Positions: 3 - Connector Rows: 1 - Connector Type: Headers and Wire Housings - Connector Gender: Male - Connector Pitch: 2.54mm **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J9 — [22-28-4033](https://www.flux.ai/adrian95/22-28-4033~4k2.md) - Datasheet URL: https://www.molex.com/pdm_docs/sd/022284033_sd.pdf - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: 0022284033 - Connector Pitch: 2.54mm - Connector Type: Headers and Wire Housings - Connector Gender: Male - Connector Rows: 1 - Connector Positions: 3 - Manufacturer Name: Molex **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### U1 — [PCA9685PW](https://www.flux.ai/kicad-part-library/pca9685pw~kzn.md) - Role Details: Chip 1, address 0x40, A0-A5 tied to GND, VDD=5.1V, OE shared with STM32 PC7/D9 - Datasheet URL: http://www.nxp.com/docs/en/data-sheet/PCA9685.pdf - Manufacturer Part Number: PCA9685PW - Package or Case Code: TSSOP-28_4.4x9.7mm_P0.65mm - Manufacturer Name: NXP Semiconductors NV - Role: PWM Controller **Pins:** - ~{OE} [pin 23] - A0 [pin 1] - A1 [pin 2] - A2 [pin 3] - A3 [pin 4] - A4 [pin 5] - A5 [pin 24] - EXTCLK [pin 25] - LED0 [pin 6] - LED1 [pin 7] - LED10 [pin 17] - LED11 [pin 18] - LED12 [pin 19] - LED13 [pin 20] - LED14 [pin 21] - LED15 [pin 22] - LED2 [pin 8] - LED3 [pin 9] - LED4 [pin 10] - LED5 [pin 11] - LED6 [pin 12] - LED7 [pin 13] - LED8 [pin 15] - LED9 [pin 16] - SCL [pin 26] - SDA [pin 27] - VDD [pin 28] - VSS [pin 14] ### U2 — [PCA9685PW](https://www.flux.ai/kicad-part-library/pca9685pw~kzn.md) - Datasheet URL: http://www.nxp.com/docs/en/data-sheet/PCA9685.pdf - Role Details: Chip 2, address 0x41, A0 tied to VCC and A1-A5 tied to GND, VDD=5.1V, OE shared with STM32 PC7/D9 - Role: PWM Controller - Manufacturer Part Number: PCA9685PW - Package or Case Code: TSSOP-28_4.4x9.7mm_P0.65mm - Manufacturer Name: NXP Semiconductors NV **Pins:** - ~{OE} [pin 23] - A0 [pin 1] - A1 [pin 2] - A2 [pin 3] - A3 [pin 4] - A4 [pin 5] - A5 [pin 24] - EXTCLK [pin 25] - LED0 [pin 6] - LED1 [pin 7] - LED10 [pin 17] - LED11 [pin 18] - LED12 [pin 19] - LED13 [pin 20] - LED14 [pin 21] - LED15 [pin 22] - LED2 [pin 8] - LED3 [pin 9] - LED4 [pin 10] - LED5 [pin 11] - LED6 [pin 12] - LED7 [pin 13] - LED8 [pin 15] - LED9 [pin 16] - SCL [pin 26] - SDA [pin 27] - VDD [pin 28] - VSS [pin 14] ### U3 — [TXS0102DCU](https://www.flux.ai/kicad-part-library/txs0102dcu~ql.md) - Manufacturer Name: Texas Instruments Inc. - Package or Case Code: VSSOP-8_2.3x2mm_P0.5mm - Manufacturer Part Number: TXS0102DCU - Datasheet URL: http://www.ti.com/lit/gpn/txs0102 - Role: I2C Level Shifter - Role Details: A side at 3.3V from Raspberry Pi, B side at 5.1V logic rail; A1/B1=SDA and A2/B2=SCL **Pins:** - A1 [pin 5] - A2 [pin 4] - B1 [pin 8] - B2 [pin 1] - GND [pin 2] - OE [pin 6] - VCCA [pin 3] - VCCB [pin 7] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/deff4rk3/dual-pca9685-servo-controller~3a](https://www.flux.ai/deff4rk3/dual-pca9685-servo-controller~3a).* --- *Generated from [https://www.flux.ai/deff4rk3/dual-pca9685-servo-controller~3a](https://www.flux.ai/deff4rk3/dual-pca9685-servo-controller~3a)*