48V to 12V. Eight layers. One PCB.
This project documents the complete design process of a DC-DC synchronous buck converter evaluation module based on the Texas Instruments LM5146-Q1 controller. The design targets the 48V bus voltage common in automotive and industrial embedded systems, stepping down to a regulated 12V rail at up to 6A output current.
The work covers the full hardware design lifecycle: component selection and calculation, schematic capture, multi-layer PCB layout with copper polygon pours, IPC-2221B clearance compliance for high-voltage nets, and integration of test points for every key signal in the circuit.
Electrical parameters
| PARAMETER | VALUE |
|---|---|
| Input voltage range | 15V – 80V |
| Typical input voltage | 48V |
| Output voltage | 12V |
| Maximum output current | 6A |
| Target efficiency | 96% |
| Switching frequency | 400 kHz |
| Inductor (LF) | 18 µH |
| Output capacitor | 3 × 22 µF ceramic |
| Input capacitor | 4 × 4.7 µF + decoupling |
Layout and physical design
8-LAYER STACKUP
8-layer board chosen for optimal power distribution and EMI performance, cost-optimised for Eurocircuits fabrication.
IPC-2221B COMPLIANCE
0.6 mm minimum clearance on all high-voltage nets (up to 80V) per IPC-2221B spacing requirements.
COPPER POLYGON POURS
Filled copper areas dedicated to power distribution across multiple layers for thermal and current carrying.
7 TEST POINTS
Dedicated measurement points: VIN, SYNC OUT, PGOOD, FB, VOUT, SW, and GND for full signal verification.
| PHYSICAL | VALUE |
|---|---|
| Board dimensions | 65 mm × 40 mm |
| Layer count | 8 layers |
| Min. clearance (HV) | 0.6 mm (IPC-2221B) |
| Fabrication cost | ~€201.70 per unit |
