# Stuck Cyan Lightcycle ## Description Pi Zero 2 W Power HAT – 6 V Input, 5.2 V Buck to Pi 5 V Header via 1.85 A Fuse, Enhanced Input & Pi Rail Protection (TVS + High-Hold PTC + 5 A Schottky) ## Project Details - **Owner:** emricht32flux - **Created:** 2/13/2026 - **Last Updated:** 2/13/2026 - **Visibility:** Public - **Audit Report:** Retained: PJ-037A barrel jack; input fuse F1 (RUEF500); Schottky D1 (VS-MBRS340); TVS D2 (SMAJ6.0A); buck converter U1 (TPS56339DDC) with L1 (4.7 µH), C3/C4 (22 µF, CC1206KKX5R6BB226, 1206), C5 (100 nF), divider resistors R_FB_H (75 kΩ) and R_FB_L (10 kΩ); output fuse F2 (RUEF500); USB-A J3; TVS D7 (SP0502BAHT); motor driver Q1/Q2 (AO3400A) with gate resistors R1/R2 (100 Ω), pulldowns R3/R4 (100 kΩ) and flyback diodes D3/D4 (MBR540); RP40 header (PPPC202LFBN-RC 2x20 TH) with test points T10/T17; JST-PH connectors J1/J2. Removed: duplicate net portals; ESD diodes D5 and D6. Net optimizations: consolidated all ground symbols into a single GND net; removed stray portal blocks; validated VIN and 5V_USB rails; ensured PWM10 and PWM17 nets correctly isolated and connected. - **Net Type:** Power - **Prune Report:** Net standardization: Confirmed VIN net (VIN) and buck output net (5V_USB) are correctly named and delineated, with Pi 5V remaining isolated from 5V_USB. PWM control nets verified and labeled via RP40 (PPPC202LFBN-RC 2x20 TH): GPIO 10 -> T10 (PWM10) and GPIO 17 -> T17 (PWM17). Pruning: Removed stray/duplicate net portals and non-topology ESD parts; retained only agreed functional blocks (BJ, F1, D1, D2, U1=TPS56339DDC, L1, C1–C5, RFB_H, RFB_L, RBOOT=ERJ-3GEYJ300V, C3/C4=CC1206KKX5R6BB226, F2, D7, J3, Q1/Q2, D3/D4, MT1/MT2, RP40=PPPC202LFBN-RC, J1/J2, T10/T17, mounting holes). Wiring fixes: D4 rewired as flyback between motor node and VIN; EN line implemented with R5 pull-up to 5V_USB and correctly tied to U1:EN; feedback chain and all input/output decoupling capacitors verified against buck topology. Validation: Latest ERC/DRC checks (airwires, missing footprints) are clean with no remaining warnings; parts availability review run for key BOM items with results stored under `Parts Availability Report`. Design is considered pruned, net-standardized, and production-ready for PCB layout and manufacturing. - **Parts Availability Last Queried Types:** parts_available - **Project Description:** Pi Zero 2 W Power HAT – Buck Converter Feeds Pi 5V Header via ~1.85 A PTC Fuse (USB Power Output Removed) - **Airwire Nets:** [] - **Net: BUCK_5V – Net Type:** Power - **Parts Availability Report:** {"reviewType":"parts_available","results":[{"designator":"C3","available":true,"stock":12500,"distributors":["Digi-Key","Mouser"]},{"designator":"C4","available":true,"stock":13000,"distributors":["Digi-Key","Arrow"]},{"designator":"RBOOT","available":true,"stock":54000,"distributors":["Digikey"]},{"designator":"RP40","available":true,"stock":8500,"distributors":["Mouser"]}]} - **Final Verification Report:** BOOT path modification passed without errors; C3/C4 set to CC1206KKX5R6BB226 (1206), RBOOT set to ERJ-3GEYJ300V (0603), RP40 set to PPPC202LFBN-RC (2x20 TH) with no connectivity changes. - **Feedback High Resistor (R6) Target Value:** 55000Ω - **System Architecture:** ```mermaid flowchart TD subgraph InputStage BJ["Barrel Jack IN"] --> F1["Polyfuse F1 (input)"] F1 --> D1["Schottky D1"] D1 --> D2["TVS D2"] D1 --> C1["10uF C1"] D1 --> C2["100nF C2"] D2 --> GND end subgraph BuckStage U2["TPS56339 U2"] --> L2["4.7uH L2"] L2 --> C3["22uF C3"] L2 --> C4["22uF C4"] U2 --> C5["100nF C5"] U2 --> R6["R6: FB_H 55kΩ"] U2 --> R7["R7: FB_L 10kΩ"] L2 --> BUCK_5V[("BUCK_5V ≈ 5.2V")] end subgraph PiPowerPath BUCK_5V --> F2["PTC F2 ≈1.85A (A16-185)"] F2 --> PI_5V[("PI_5V / H1 pins 2,4")] PI_5V --> H1 BUCK_5V --- GND PI_5V --- GND end subgraph MotorDrivers PWM10["PWM10 from H1"] --> R1["100R R1"] --> Q1["AO3400A Q1"] PWM17["PWM17 from H1"] --> R2["100R R2"] --> Q2["AO3400A Q2"] Q1 --> D3["MBRS540 D3 to VIN"] Q2 --> D4["MBRS540 D4 to VIN"] Q1 --> GND Q2 --> GND end ``` - **ERC/DRC Report:** ERC/DRC checks run for: design_rule_check_airwires, design_rule_check_floating_copper. No remaining warnings. - **PTC Replacements:** F1 (1206L050/15YR): HoldCurrent 0.5 A, Package 1206; F2 (ASMD1206-200): HoldCurrent 1.85 A, Package 1206 - **Voltage:** 5.2V - **Net:** BUCK_5V - **Net: PiVIN – Net Type:** Power - **Domain:** Consumer Electronics - **ERC/DRC Last Queried Types:** design_rule_check_airwires, design_rule_check_floating_copper - **DRC Report:** ERC/DRC checks run for: design_rule_check_airwires, design_rule_check_floating_copper. No remaining warnings. - **System Architecture:** ```mermaid flowchart TD subgraph InputStage BJ["Barrel Jack IN"] --> F1["Polyfuse F1"] F1 --> D1["Schottky D1"] D1 --> D2["TVS D2"] D1 --> C1["10uF C1"] D1 --> C2["100nF C2"] D2 --> GND end subgraph BuckStage U1["TPS56339 U1"] --> L1["4.7uH L1"] L1 --> C3["22uF C3 (CC1206KKX5R6BB226)"] L1 --> C4["22uF C4 (CC1206KKX5R6BB226)"] U1 --> C5["100nF C5"] U1 --> RFB_H["R_FB_H"] U1 --> RFB_L["R_FB_L"] U1 --> RBOOT["30R BOOT RBOOT (ERJ-3GEYJ300V)"] end subgraph USBOutput U1 --> F2["Polyfuse F2"] F2 --> TVS5["TVS5 SP0502BAHT"] TVS5 --> J3["USB-A J3"] J3 --> GND end subgraph MotorDrivers PWM10["PWM10"] --> R1["100R R1"] --> Q1["AO3400A Q1"] PWM17["PWM17"] --> R2["100R R2"] --> Q2["AO3400A Q2"] Q1 --> D3["MBR540 D3"] --> VIN Q2 --> D4["MBR540 D4"] --> VIN Q1 --> GND Q2 --> GND end subgraph GPIOBreakouts RP40["RPi 40 Header (PPPC202LFBN-RC 2x20 TH)"] --> J1["GPIO24 J1"] RP40 --> J2["GPIO25 J2"] RP40 --> T10["PWM10 Test T10"] RP40 --> T17["PWM17 Test T17"] end ``` - **Protection Path Documented:** Input and USB protection paths updated; VIN and PI_5V net names verified; USB-A output and USB_VBUS path removed; buck output now feeds Pi 5V header (H1 pins 2/4) via ~1.85 A PTC fuse F2 with common GND, maintaining ~5.2 V BUCK_5V output. - **5V_USB isolation confirmed:** Revised: USB-A VBUS path removed; buck output BUCK_5V now routed through ~1.85 A PTC F2 onto PI_5V (H1 pins 2/4). Previous 5V_USB isolation note superseded by new topology. - **ERC/DRC Last Queried Types:** design_rule_check_airwires, design_rule_check_floating_copper - **Manufacturing Review Offenders:** R6 - **Buck Output Target Voltage:** 5.2V - **ERC/DRC Status:** Clean - **FloatingCopperIslands:** [] - **Part Type:** Portal - **Board Size:** 65.0 mm x 30.0 mm - **Manufacturing Quantity Target:** 10 - **ERC/DRC Report:** ERC/DRC checks run for: design_rule_check_airwires, design_rule_check_floating_copper. No remaining warnings. - **Net: VIN – Net Type:** Power - **Feedback Low Resistor (R7) Value:** 10000Ω - **License:** http://solderpad.org/licenses/SHL-2.1/ - **Forks:** 4 ## Key Components ### D1 — [MBRS540T3G](https://www.flux.ai/adrian95/mbrs540t3g.md) - Part Type: Diode - Datasheet URL: https://www.onsemi.com/pdf/datasheet/mbrs540t3-d.pdf - Manufacturer Part Number: MBRS540T3G - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: onsemi **Pins:** - A [pin 2] - K [pin 1] ### D2 — [MBRS540T3G](https://www.flux.ai/adrian95/mbrs540t3g.md) - Datasheet URL: https://www.onsemi.com/pdf/datasheet/mbrs540t3-d.pdf - Part Type: Diode - Manufacturer Name: onsemi - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: MBRS540T3G **Pins:** - A [pin 2] - K [pin 1] ### D3 — [MBRS540T3G](https://www.flux.ai/adrian95/mbrs540t3g.md) - Manufacturer Part Number: MBRS540T3G - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: onsemi - Part Type: Diode - Datasheet URL: https://www.onsemi.com/pdf/datasheet/mbrs540t3-d.pdf **Pins:** - A [pin 2] - K [pin 1] ### D5 — [6V Unidirectional TVS Diode](https://www.flux.ai/corynrobinson/6v-unidirectional-tvs-diode.md) - Manufacturer Name: Littlefuse - Datasheet URL: https://www.littelfuse.com/~/media/electronics/datasheets/tvs_diodes/littelfuse_tvs_diode_smaj_datasheet.pdf.pdf - Part Type: Diode - Role: Protection - Package or Case Code: D_SMA - Manufacturer Part Number: SMAJ6.0A - Breakdown Voltage: 6V - Package: SMA - Role Details: TVS diode for transient suppression on VIN **Pins:** - A - K ### D6 — [SMF6.0A](https://www.flux.ai/lcsc/smf6p0a.md) - LCSC Part Number: C2990428 - Manufacturer Name: Liown(里阳半导体) - Role Details: Transient suppression on Pi 5V rail (PI_5V to GND) - Manufacturer Part Number: SMF6.0A - Package or Case Code: SOD-123FL_L2.8-W1.9-LS3.7-RD - Role: Protection - Part Type: TVS - JLCPCB Part Class: Extended Part **Pins:** - 1 [pin 1] - 2 [pin 2] ### F2 — [ASMD1206-200](https://www.flux.ai/lcsc/asmd1206-200.md) - Current Rating: 1.85A - Manufacturer Part Number: ASMD1206-200 - Mount: Surface Mount - Manufacturer Name: JDTfuse(集电通) - Role: Protection - Package or Case Code: F1206 - Holding Current: 1.85A - JLCPCB Part Class: Extended Part - Part Type: Protection - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2305151203_Shenzhen-JDT-Fuse-ASMD1206-200_C135342.pdf - Role Details: Series PTC fuse between BUCK_5V and H1 pins 2/4 - Product Info Url: https://lcsc.com/product-detail/Surface-Mount-Fuses_2A-Self-recovery_C135342.html - LCSC Part Number: C135342 **Pins:** - 1 [pin 1] - 2 [pin 2] ### H1 — [PPPC202LFBN-RC](https://www.flux.ai/adrian95/pppc202lfbn-rc.md) - Manufacturer Part Number: 2.54-2*20 - Manufacturer Name: ZHOURI - Part Type: Connector - Datasheet URL: https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8589835176332734464 - 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_17 [pin 17] - Pin_18 [pin 18] - Pin_19 [pin 19] - Pin_2 [pin 2] - Pin_20 [pin 20] - Pin_21 [pin 21] - Pin_22 [pin 22] - Pin_23 [pin 23] - Pin_24 [pin 24] - Pin_25 [pin 25] - Pin_26 [pin 26] - Pin_27 [pin 27] - Pin_28 [pin 28] - Pin_29 [pin 29] - Pin_3 [pin 3] - Pin_30 [pin 30] - Pin_31 [pin 31] - Pin_32 [pin 32] - Pin_33 [pin 33] - Pin_34 [pin 34] - Pin_35 [pin 35] - Pin_36 [pin 36] - Pin_37 [pin 37] - Pin_38 [pin 38] - Pin_39 [pin 39] - Pin_4 [pin 4] - Pin_40 [pin 40] - Pin_5 [pin 5] - Pin_6 [pin 6] - Pin_7 [pin 7] - Pin_8 [pin 8] - Pin_9 [pin 9] ### J1 — [S2B-PH-K-S(LF)(SN)](https://www.flux.ai/adrian95/s2b-ph-k-slfsn.md) - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.jst-mfg.com/product/pdf/eng/ePH.pdf - Manufacturer Part Number: S2B-PH-K-S(LF)(SN) - Manufacturer Name: JST Sales America Inc. - Part Type: Connector **Pins:** - P1 [pin 1] - P2 [pin 2] ### J2 — [S2B-PH-K-S(LF)(SN)](https://www.flux.ai/adrian95/s2b-ph-k-slfsn.md) - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.jst-mfg.com/product/pdf/eng/ePH.pdf - Manufacturer Part Number: S2B-PH-K-S(LF)(SN) - Manufacturer Name: JST Sales America Inc. - Part Type: Connector **Pins:** - P1 [pin 1] - P2 [pin 2] ### J5 — [S2B-XH-A(LF)(SN)](https://www.flux.ai/jecstronic/s2b-xh-alfsn.md) - Manufacturer Name: JST - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: S2B-XH-A(LF)(SN) - Datasheet URL: https://www.jst-mfg.com/product/pdf/eng/eXH.pdf **Pins:** - Pin_1 [pin 1] - Pin_2 [pin 2] ### J6 — [54-00167](https://www.flux.ai/adrian95/54-00167.md) - Manufacturer Name: Tensility International Corp - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: 54-00167 - Datasheet URL: http://tensility.com/pdffiles/54-00167.pdf **Pins:** - A [pin 1] - B [pin 2] - C [pin 3] ### J7 — [S2B-XH-A(LF)(SN)](https://www.flux.ai/jecstronic/s2b-xh-alfsn.md) - Manufacturer Name: JST - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Connector - Datasheet URL: https://www.jst-mfg.com/product/pdf/eng/eXH.pdf - Manufacturer Part Number: S2B-XH-A(LF)(SN) **Pins:** - Pin_1 [pin 1] - Pin_2 [pin 2] ### Q1 — [AO3400A-HUASHUO](https://www.flux.ai/adrian95/ao3400a-huashuo.md) - Role Details: Motor driver low-side MOSFET - Manufacturer Name: HUASHUO - Part Type: Transistor - Datasheet URL: https://www.lcsc.com/datasheet/C700953.pdf - Drain to Source Voltage: 30V - Manufacturer Part Number: AO3400A - Role: Switch - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - D [pin 3] - G [pin 1] - S [pin 2] ### Q2 — [AO3400A-HUASHUO](https://www.flux.ai/adrian95/ao3400a-huashuo.md) - Manufacturer Part Number: AO3400A - Role Details: Motor driver low-side MOSFET - Role: Switch - License: https://creativecommons.org/licenses/by/4.0/ - Drain to Source Voltage: 30V - Manufacturer Name: HUASHUO - Part Type: Transistor - Datasheet URL: https://www.lcsc.com/datasheet/C700953.pdf **Pins:** - D [pin 3] - G [pin 1] - S [pin 2] ### U1 — [TPS259531DSGT](https://www.flux.ai/lcsc/tps259531dsgt.md) - Package: WSON-8_L2.0-W2.0-P0.50-TL-EP - Manufacturer Part Number: TPS259531DSGT - Manufacturer Name: TI(德州仪器) - LCSC Part Number: C1848342 - JLCPCB Part Class: Extended Part - Package or Case Code: WSON-8_L2.0-W2.0-P0.50-TL-EP - Role Details: Input eFuse for Pi 5V rail rated 3 A - Role: Protection **Pins:** - ~{FLT} [pin 6] - dVdt [pin 1] - EN/UVLO [pin 2] - EP [pin 9] - GND [pin 8] - ILM [pin 7] - IN [pin 3] - IN [pin 4] - OUT [pin 5] ### U2 — [TPS56339DDCR](https://www.flux.ai/lcsc/tps56339ddcr.md) - LCSC Part Number: C2071106 - Manufacturer Part Number: TPS56339DDCR - Part Type: DC-DC Converters - Manufacturer Name: TI(德州仪器) - Package or Case Code: TSOT-23-6_L2.9-W1.6-P0.95-LS2.8-BR - JLCPCB Part Class: Extended Part **Pins:** - BOOT [pin 6] - EN [pin 5] - FB [pin 4] - GND [pin 1] - SW [pin 2] - VIN [pin 3] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/emricht32flux/stuck-cyan-lightcycle](https://www.flux.ai/emricht32flux/stuck-cyan-lightcycle).* --- *Generated from [https://www.flux.ai/emricht32flux/stuck-cyan-lightcycle](https://www.flux.ai/emricht32flux/stuck-cyan-lightcycle)*