# Placement rules (derived)

| type | constraint | weight | why |
|---|---|---|---|
| fixed | H |  | mechanical (mounting hole / no net) |
| fixed | U1 |  | module: antenna flush with the top edge |
| fixed | J4 |  | connector (mechanical interface) |
| fixed | E1 |  | connector (mechanical interface) |
| fixed | J2 |  | battery connector at the left edge |
| fixed | U2 |  | LDO position |
| fixed | J1 |  | USB-C at the bottom edge |
| fixed | U4 |  | sensor zone below the module, away from the heat sources |
| fixed | C14 |  | GPS decoupling beside the module edge |
| fixed | C15 |  | GPS decoupling beside the module edge |
| fixed | U7 |  | GPS module on the bottom, antenna up when flipped |
| fixed | C16 |  | GPS decoupling beside the module edge |
| fixed | U5 |  | charger position |
| fixed | U3 |  | sensor zone below the module, away from the heat sources |
| fixed | D2 |  | LED |
| fixed | D4 |  | LED |
| fixed | D3 |  | LED |
| fixed | U6 |  | ESD next to the USB-C |
| fixed | SW1 |  | BOOT button, right edge |
| fixed | SW2 |  | RESET button, left edge |
| fixed | BZ1 |  | piezo on the bottom |
| loop | loop U2.4 → C3.1 → C3.2 → U2.2 ≤ 6.0 mm² | 20.0 | buck U2 input hot loop via C3 |
| near | C3.1 ≤ 1.5 mm from U2.4 | 15.0 | buck U2 input cap |
| near | R13.2 ≤ 2.5 mm from U2.5 | 6.0 | buck U2 feedback divider |
| near | R14.1 ≤ 2.5 mm from U2.5 | 6.0 | buck U2 feedback divider |
| apart | net FB ≥ 1.0 mm from net SW | 5.0 | buck U2 FB away from switch node |
| near | C7.1 ≤ 0.85 mm from U3.10 (pad edge to edge) | 10.0 | decoupling U3 VDD (+3V3), 100nF |
| near | C8.1 ≤ 0.85 mm from U3.1 (pad edge to edge) | 10.0 | decoupling U3 VDDIO (+3V3), 100nF |
| near | C9.1 ≤ 0.85 mm from U4.5 (pad edge to edge) | 10.0 | decoupling U4 Vdd_IO (+3V3), 100nF |
| near | C14.1 ≤ 0.85 mm from U7.8 (pad edge to edge) | 10.0 | decoupling U7 VCC (+3V3), 100nF |
| near | C16.1 ≤ 0.85 mm from U7.6 (pad edge to edge) | 10.0 | decoupling U7 VBAT (+3V3), 100nF |
| near | C6.1 ≤ 0.85 mm from U1.2 (pad edge to edge) | 10.0 | decoupling U1 VDD (+3V3), 100nF |
| near | C11.1 ≤ 0.85 mm from U4.8 (pad edge to edge) | 10.0 | decoupling U4 Vdd (+3V3), 100nF |
| near | C21.1 ≤ 0.85 mm from U10.6 (pad edge to edge) | 10.0 | decoupling U10 VDD (+3V3), 100nF |
| near | C5.1 ≤ 5.35 mm from U1.2 (pad edge to edge) | 3.0 | bulk cap on +3V3 (10uF) near U1 (anchor chosen by proximity) |
| near | C10.1 ≤ 5.35 mm from U4.5 (pad edge to edge) | 3.0 | bulk cap on +3V3 (10uF) near U4 (anchor chosen by proximity) |
| near | C15.1 ≤ 5.35 mm from U7.8 (pad edge to edge) | 3.0 | bulk cap on +3V3 (10uF) near U7 (anchor chosen by proximity) |
| near | C4.1 ≤ 5.35 mm from U4.5 (pad edge to edge) | 3.0 | bulk cap on +3V3 (22uF) near U4 (anchor chosen by proximity) |
| near | C1.1 ≤ 2.35 mm from F1.2 (pad edge to edge) | 4.0 | F1 filter bulk cap 4.7uF at the bead output |
| closer | C9.1 closer to U4.5 than C10.1 | 2.0 | C9 (smaller) closer to U4.5 than C10 |
| closer | C10.1 closer to U4.5 than C4.1 | 2.0 | C10 (smaller) closer to U4.5 than C4 |
| closer | C14.1 closer to U7.8 than C15.1 | 2.0 | C14 (smaller) closer to U7.8 than C15 |
| closer | C6.1 closer to U1.2 than C5.1 | 2.0 | C6 (smaller) closer to U1.2 than C5 |
| near | C12.1 ≤ 2.0 mm from U1.3 | 5.0 | C12 (1uF) filters U1 EN (EN) |
| near | C18.1 ≤ 2.0 mm from U2.1 | 5.0 | C18 (1uF) filters U2 EN (BUCK_EN) |
| near | C13.1 ≤ 2.0 mm from U1.18 | 5.0 | C13 (100nF) filters U1 IO10 (VBAT_SENSE) |
| near | L4.1 ≤ 3.0 mm from C20.2 | 2.0 | filter L4 feeds its cap C20 |
| near | F1.2 ≤ 3.0 mm from C1.1 | 2.0 | filter F1 feeds its cap C1 |

## Review

- **WARN** WEAK_ANCHOR C10: C10 anchored only by proximity: bulk cap on +3V3 (10uF) near U4 (anchor chosen by proximity)
- **WARN** WEAK_ANCHOR C15: C15 anchored only by proximity: bulk cap on +3V3 (10uF) near U7 (anchor chosen by proximity)
- **WARN** UNANCHORED C17: C17 (1uF) has no placement rule
- **WARN** UNANCHORED C19: C19 (100nF) has no placement rule
- **WARN** UNANCHORED C2: C2 (10uF) has no placement rule
- **WARN** WEAK_ANCHOR C4: C4 anchored only by proximity: bulk cap on +3V3 (22uF) near U4 (anchor chosen by proximity)
- **WARN** WEAK_ANCHOR C5: C5 anchored only by proximity: bulk cap on +3V3 (10uF) near U1 (anchor chosen by proximity)
- **WARN** UNANCHORED L1: L1 (2.2uH) has no placement rule
- **WARN** UNANCHORED L2: L2 (2.4nH) has no placement rule
- **WARN** UNANCHORED L3: L3 (5.6nH) has no placement rule