Simulation｜

Thermal Simulation of Linear RegulatorsPCB Conditions for Thermal Simulation Models

2025.01.23

Points of this article

・The PCB conditions for thermal simulation model are described for the BD4xxMxEFJ series.

table of contents

・1-layer PCB (1s)
・2-Layer PCB (2s)
・4-layer PCB (2s2p)

The BD4xxMxEFJ, BD4xxMxFP, and BD4xxMxFP2 series have different PCB specifications. For each of the specifications, refer to the application notes listed in the “Links to Related Documents” at the end of this article.

1-layer PCB (1s)

The 1-layer PCB is compliant with JEDEC standard JESD51-3. PCBs with different copper foil areas are shown below.

Top layer Trace

1 layer PCB specifications
Item	Value
Board thickness	1.57mm
Board outline dimensions	76.2mm × 114.3mm
Board material	FR-4
Trace thickness (Finished thickness)	70um（2 oz）
Lead width	0.254mm
Copper foil area	Footprint、100mm²、600mm²、1200mm²

Footprint dimentions,Cross-section of 1 layer board

2-Layer PCB (2s)

The 2-layer PCB conforms to JEDEC standards JESD51-5 and JESD51-7. PCBs with different copper foil areas are shown below.

Top layer Trace, Bottom layer Trace

2 layer PCB specifications
Item		Value
Board thickness		1.60mm
Board outline dimensions		76.2mm × 114.3mm
Board material		FR-4
Trace thickness (Finished thickness)	Top	70um（2 oz）
Trace thickness (Finished thickness)	Bottom	70um（2 oz）
Lead width		0.254mm
Copper foil area	Top	Footprint
Copper foil area	Bottom	100mm², 300mm², 600mm², 1200mm², 2000mm², 5500mm²

Footprint dimentions,Cross-section of 2 layer board

4-layer PCB (2s2p)

The 4-layer PCB conforms to JEDEC standards JESD51-5 and JESD51-7. PCBs with different copper foil areas are shown below.

Top Layer Trace,Middle 1 Layer Trace,Middle 2 Layer Trace,Bottom Layer Trace

4 layer PCB specifications
Item		Value
Board thickness		1.60mm
Board outline dimensions		76.2mm × 114.3mm
Board material		FR-4
Trace thickness (Finished thickness)	Top	70um（2 oz）
	Middle 1	35um（1 oz）
	Middle 2	35um（1 oz）
	Bottom	70um（2 oz）
Lead width		0.254mm
Copper foil area	Top	Footprint
	Middle 1	5505mm2（74.2mm × 74.2mm）
	Middle 2	5505mm2（74.2mm × 74.2mm）
	Bottom	5505mm2（74.2mm × 74.2mm）

Footprint dimentions,Cross-section of 4 layer board

Links to Related Documents

Please refer to the links for product specifications:

Please refer to the links for application notes on thermal resistance.

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