Raspberry Pi Zero HAT PCB Design

0:06

Work done

Re-audited the live schematic against the remaining plan.
Added the missing eFuse support parts: C7 = 3.3 nF for U1:dVdt and R10 = 100 kΩ for U1:~FLT pull-up.
Confirmed current remaining schematic issues: L2:1 is still floating, J2:P1 is still floating, U1:dVdt/U1:~FLT and new C7/R10 are not yet wired, J6:C still needs explicit NC, TP3 remains a single-pin net, and 41 Net Portals remain.
Updated the handoff mapping with the current blocked state and exact intended repairs: Schematic Text Mapping for Other LLMs.

Success criteria review

✅ Verified existing corrected intent for VIN_6V, BUCK_5V, PI_5V, motors, LED GPIO JSTs, common GND, and feedback values.
✅ Added C7 and R10 parts needed for the eFuse omissions.
❌ Could not safely apply final wiring repairs due to a schematic data issue that is blocking edits.
❌ ERC is not clean yet; remaining warnings include L2:1, J2:P1, U1:dVdt, U1:~FLT, C7, R10, J6:C, TP3, and expected unused Pi header pins.
❌ PCB layout preparation should wait until the schematic edit issue is cleared and the final schematic repairs are verified.

Next steps

Clear the schematic edit issue, then apply the documented repairs: connect L2:1 to U2:SW/C5:P2, connect J2:P1 to MOTOR1_LOW, wire C7 and R10, mark J6:C NC, resolve TP3, remove stale portals, then rerun ERC/DRC before PCB layout setup.

2 days

bubbaa

give a text instructions of exactly what to wire but dont wire yourself.

2 days

flux

1:08

Considering user instructions.

I created a detailed copy-pasteable wiring checklist here: Manual Wiring Instructions - Pi Zero 2 W Power HAT.

It lists the exact pin-to-pin/net wiring for VIN_6V, GND, TPS56339 buck/BOOT/SW/FB, TPS259531 eFuse, motor MOSFET channels, LED JSTs, TP3, and the final ERC checklist.

2 days

bubbaa

I think I wired everything. check my work. do not wire anything yourself but call out what is needed.

2 days

flux

1:25

Considering tool usage for files.

Running design review.

Analyzing the schematic.

Your main functional wiring looks mostly correct now: VIN_6V, buck/eFuse-to-PI_5V, motor low-side switching, LED GPIO connectors, and common GND are all largely in place. Remaining issues are cleanup/ERC hygiene: label the unnamed VIN_6V, BUCK_5V, and GND nets, rename AUTO_NAME to Q2_GATE, mark J6:C NC, resolve/assign TP1–TP4 and 6V:P1, then route the PCB airwires. Full audit is in Schematic Audit — Check My Work.

Run ERC/DRC

List net labels

Check BOM completeness

Inspect airwires

2 days

Refine this doc

Ask about this doc

Schematic Text Mapping for Other LLMs

Project intent

Raspberry Pi Zero 2 W HAT corrected topology:

Tensility 54-00166 barrel jack input with J6:A = VIN_6V, J6:B = GND, and J6:C = NC / unused switch contact.
U2 = TPS56339DDCR buck regulator converts raw 6 V to about 5.2 V.
Buck output BUCK_5V powers the Raspberry Pi 5 V header through F2 and the U1 = TPS259531DSGT eFuse/protection stage.
Motors remain on raw VIN_6V and are switched with low-side N-MOSFETs.
All grounds are common.
LED connectors J5 and J7 expose only GPIO24/GPIO25 plus GND and are for LED modules with built-in current limiting unless additional series resistors/drivers are added.

Important designator convention

Current schematic uses:

U2 = TPS56339DDCR buck regulator.
U1 = TPS259531DSGT eFuse / protection IC for the Pi 5 V rail.
H1 = Raspberry Pi 40-pin header.
J6 = Tensility barrel jack.

Current verified net mapping

VIN_6V raw 6 V rail

Expected corrected mapping:

J6:A
U2:VIN
U2:EN
C1:P1, C2:P1, C6:1
D5:K VIN TVS cathode
D2:K, D3:K flyback diode cathodes
J2:P2, J1:P2 motor positive pins

GND common ground

Expected corrected mapping:

J6:B
U2:GND
U1:GND, U1:EP
Raspberry Pi ground pins including H1:Pin_6, H1:Pin_9, H1:Pin_14, H1:Pin_25, H1:Pin_34, H1:Pin_39
Q1:S, Q2:S
R3:2, R4:2, R7:P2, R_ILM:P2
C1:P2, C2:P2, C3:2, C4:2, C6:2
D5:A, D1:2
J5:Pin_2, J7:Pin_2

Buck regulator U2 / TPS56339

Input: U2:VIN -> VIN_6V; U2:EN -> VIN_6V for always-on operation.
Ground: U2:GND -> GND.
Switch node should be SW = U2:SW + L2:1 + C5:P2.
Bootstrap path should be U2:BOOT -> R9:1 -> R9:2 -> C5:P1 -> C5:P2 -> SW.
Output: BUCK_5V = L2:2 + C3:1 + C4:1 + F2:1 + R6:1.
Output capacitors: C3:2, C4:2 -> GND.
Feedback: FB = U2:FB + R6:2 + R7:P1; R7:P2 -> GND.
Feedback values: R6 = 76.8 kΩ, R7 = 10 kΩ, target BUCK_5V ≈ 5.2 V using the project’s ~0.6 V FB reference assumption.

Current caveat from latest audit

A post-cleanup verification showed the SW connection still needs one final repair: U2:SW and C5:P2 are together, but L2:1 is not visible on that same net. The intended required connection is still U2:SW = C5:P2 = L2:1.

Current edit blocker

Recent direct schematic edit attempts are blocked by a stale/malformed internal node reference left over from the earlier Net Portal corruption. Connection edits and Net Portal deletion attempts currently fail before they can be applied. Do not treat this as a topology contradiction; the intended repairs below remain valid and should be applied once the stale node is cleared.

Pi 5 V path through eFuse

BUCK_5V -> F2:1
F2:2 -> U1_IN
U1_IN = F2:2 + U1:IN pins + U1:EN/UVLO
PI_5V = U1:OUT + H1:Pin_2 + H1:Pin_4 + D1:1
D1:2 -> GND
R_ILM = 1.0 kΩ from U1:ILM to GND; using ILIMIT = 2000/RILM + 0.04, this programs approximately 2.04 A.
U1:dVdt and U1:~FLT were flagged by ERC as floating. C7 = 3.3 nF and R10 = 100 kΩ were added to the schematic, but their connections could not be verified/applied because of the stale-node edit blocker. Intended final wiring: C7:P1 -> U1:dVdt, C7:P2 -> GND, R10:P1 -> U1:~FLT, R10:P2 -> PI_5V.

Motor channel 1

VIN_6V -> J2:P2 motor positive.
MOTOR1_LOW = J2:P1 + Q1:D + D2:A.
Q1:S -> GND.
Flyback: D2:K -> VIN_6V, D2:A -> MOTOR1_LOW.
Control: PWM10 = H1:Pin_19 + R1:1.
Gate: Q1_GATE = R1:2 + R3:1 + Q1:G.
Pulldown: R3:2 -> GND.

Motor channel 2

VIN_6V -> J1:P2 motor positive.
MOTOR2_LOW = J1:P1 + Q2:D + D3:A.
Q2:S -> GND.
Flyback: D3:K -> VIN_6V, D3:A -> MOTOR2_LOW.
Control: PWM17 = H1:Pin_11 + R2:2.
Gate net is electrically Q2_GATE = R2:1 + R4:1 + Q2:G; the live schematic may still display this as AUTO_NAME due to a duplicate/colliding label.
Pulldown: R4:2 -> GND.
Note: R2 is a two-terminal series resistor, so the orientation PWM17 -> R2:2 and R2:1 -> Q2_GATE is electrically valid.

LED module connectors

GPIO24_LED = H1:Pin_18 + J5:Pin_1; J5:Pin_2 -> GND.
GPIO25_LED = H1:Pin_22 + J7:Pin_1; J7:Pin_2 -> GND.
These are GPIO + GND only. Use only with LED modules that already include current limiting; bare LEDs require series resistors or a transistor/MOSFET driver.

Machine-readable mapping

Yaml
designators:
  pi_header: H1
  barrel_jack: J6
  buck_regulator: U2
  efuse: U1
  buck_inductor: L2
  buck_boot_resistor: R9
  buck_boot_capacitor: C5
  buck_feedback_high: R6
  buck_feedback_low: R7
  buck_output_caps: [C3, C4]
  efuse_input_fuse: F2
  motor1_connector: J2
  motor2_connector: J1
  motor1_mosfet: Q1
  motor2_mosfet: Q2
  motor1_flyback: D2
  motor2_flyback: D3
  led_gpio24_connector: J5
  led_gpio25_connector: J7

nets:
  VIN_6V:
    - J6:A
    - U2:VIN
    - U2:EN
    - C1:P1
    - C2:P1
    - C6:1
    - D5:K
    - D2:K
    - D3:K
    - J2:P2
    - J1:P2
  GND:
    - J6:B
    - U2:GND
    - U1:GND
    - U1:EP
    - H1:Pin_6
    - H1:Pin_9
    - H1:Pin_14
    - H1:Pin_25
    - H1:Pin_34
    - H1:Pin_39
    - Q1:S
    - Q2:S
    - R3:2
    - R4:2
    - R7:P2
    - R_ILM:P2
    - C1:P2
    - C2:P2
    - C3:2
    - C4:2
    - C6:2
    - D5:A
    - D1:2
    - J5:Pin_2
    - J7:Pin_2
  SW_intended:
    - U2:SW
    - L2:1
    - C5:P2
  BOOT:
    - U2:BOOT
    - R9:1
  BOOT_CAP:
    - R9:2
    - C5:P1
  BUCK_5V:
    - L2:2
    - C3:1
    - C4:1
    - F2:1
    - R6:1
  FB:
    - U2:FB
    - R6:2
    - R7:P1
  U1_IN:
    - F2:2
    - U1:IN
    - U1:EN/UVLO
  PI_5V:
    - U1:OUT
    - H1:Pin_2
    - H1:Pin_4
    - D1:1
  PWM10:
    - H1:Pin_19
    - R1:1
  Q1_GATE:
    - R1:2
    - R3:1
    - Q1:G
  MOTOR1_LOW:
    - J2:P1
    - Q1:D
    - D2:A
  PWM17:
    - H1:Pin_11
    - R2:2
  Q2_GATE:
    - R2:1
    - R4:1
    - Q2:G
  MOTOR2_LOW:
    - J1:P1
    - Q2:D
    - D3:A
  GPIO24_LED:
    - H1:Pin_18
    - J5:Pin_1
  GPIO25_LED:
    - H1:Pin_22
    - J7:Pin_1

Remaining verification / repair notes

Clear the stale/malformed node edit blocker, then restore/verify L2:1 on SW with U2:SW and C5:P2.
Confirm J6:C is physically marked no-connect; the design intent is NC unless used for plug detect.
Wire the newly added eFuse support parts: C7:P1 -> U1:dVdt, C7:P2 -> GND, R10:P1 -> U1:~FLT, R10:P2 -> PI_5V.
Connect J2:P1 to MOTOR1_LOW if it is still reported floating; intended MOTOR1_LOW = J2:P1 + Q1:D + D2:A.
Optional cleanup: rename the Q2 gate net from AUTO_NAME to Q2_GATE after removing any duplicate/colliding label.
Layout stage must use wider copper for VIN_6V, motor paths, BUCK_5V, and PI_5V, and keep buck SW/BOOT loops short.

Project intent

Important designator convention

Current verified net mapping

VIN_6V raw 6 V rail

GND common ground

Buck regulator U2 / TPS56339

Current caveat from latest audit

Current edit blocker

Pi 5 V path through eFuse

Motor channel 1

Motor channel 2

LED module connectors

Machine-readable mapping

Remaining verification / repair notes

Reviews

Documents

Schematic Text Mapping for Other LLMs

Manual Wiring Instructions - Pi Zero 2 W Power HAT

Schematic Audit — Check My Work

Assets

No assets added.

Project Name

Stuck Cyan Lightcycle 92e7

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)

Properties

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 Av…ed 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: BUC…et Type

Power

Parts Av…y 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 Ver…n 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…t Value

55000

System Architecture

Diagram

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

5.2

Net

BUCK_5V

Net: PiVI…Net Type

Power

Domain

Consumer Electronics

ERC/DRC…d 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

Diagram

Protecti…umented

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 i…nfirmed

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…d Types

design_rule_check_airwires, design_rule_check_floating_copper

Manufact…fenders

Buck Out… Voltage

5.2

ERC/DRC Status

Clean

Floating…rIslands

[]

Part Type

Portal

Board Size

65.0 mm x 30.0 mm

Manufact… Target

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…) Value

10000

License

solderpad.org/licenses/SHL-2.1/

Pricing & Availability

Distributor	Qty 1
Arrow	$2.51–$3.01
Digi-Key	$1.98–$3.39
LCSC	$3.43–$3.79
Mouser	$3.14–$3.44
TME	$1.46
Verical	$1.58–$91.06

Controls

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bubbaa / Stuck Cyan Lightcycle 92e7

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