pcb.md

JLCPCB

JLC04161H-7628 (1.59 mm ± 10% nominal)

Layer	Material	Thickness (mm)	Note
L1	Copper	0.035	1 oz
Prepreg	7628 (49% RC)	0.21040
L2	Copper	0.0152
Core	Core	1.065	Inner Layers: 1.1 mm nomial, H/Hoz
L3	Copper	0.0152
Prepreg	7628 (49% RC)	0.21040
L4	Copper	0.035	1 oz

• H/Hoz = 0.5 oz copper in inner layers.
• RC: Resin Content.
• Preperg thickness refers to post-lamination thickness (after compression), not supplier's specification.
• Copper thickness refers to finished thickness, not supplier's specification. For example, a 0.5 oz inner layer has a thickness of 0.0175 mm by specification, but the actual thickness is closer to 0.0152 mm due to manufacturing losses.
• Nan Ya Plastics NP-155F substrate is used by default for 4 to 8 layer PCBs.

Nan Ya Plastics NP-155F (4 to 8 layers)

Core εr

Core Thickness	εr
0.08 mm	3.99
0.10 mm	4.36
0.13 mm	4.17
0.15 mm	4.36
0.20 mm	4.36
0.25 mm	4.23
0.30 mm	4.41
0.35 mm	4.36
0.40 mm	4.36
0.45 mm	4.36
0.50 mm	4.48
0.55 mm	4.41
0.60 mm	4.36
0.65 mm	4.36
0.70 mm	4.53
> 0.70 mm	4.43

Prepreg εr

Prepreg Type	Resin	εr	Nominal Thickness
7628	49%	4.4	8.6 mil
3313 (2313)	57%	4.1	4.2 mil
1080	67%	3.91	3.3 mil
2116	54%	4.16	4.9 mil

• The given permitivities are calculated backward by measurements, not supplier's raw specification.
• Impedance calculation for reference only. JLCPCB may fine-tune these values based on measurements.

Sources

1. https://jlcpcb.com/help/article/User-Guide-to-the-JLCPCB-Impedance-Calculator
2. https://web.archive.org/web/20240805074558/https://www.jlc.com/portal/server_guide_37381.html
3. https://jlcpcb.com/pcb-impedance-calculator

OSH Park

Layer	Material	Thickness (mm)	εr	tan(δ)	Note
Silkscreen	Taiyo-SS White	0.0152	1.00
Solder Mask	Taiyo-SM Purple	0.0152	3.90	0.033
L1	Copper	0.0432			1 oz
Prepreg	FR408HR 2x2113 (57% RC)	0.1999	3.61	0.009
L2	Copper	0.0175
Core	FR408HR	0.9906	3.87	0.009	0.5 oz
L3	Copper	0.0175
Prepreg	FR408HR 2x2113 (57% RC)	0.1999	3.61	0.009
L4	Copper	0.0432			1 oz
Solder Mask	Taiyo-SS White	0.0152	3.90	0.033
Silkscreen	Taiyo-SM Purple	0.0152	1.00

• RC: Resin Content.

Sources

1. https://web.archive.org/web/20250403133536/https://docs.oshpark.com/services/four-layer/
2. https://web.archive.org/web/20250429115511/https://docs.oshpark.com/resources/four-layer-stackup.png

Simulation Inputs

JLC04161H-7628 (1.59 mm ± 10% nominal)

Layer	Material	Thickness (mm)	Parameters
L1	PEC	0
Prepreg	NP155F-7628-RC49%	0.21040	εr = 4.40
L2	PEC	0
Core	NP155F-Core	1.065	εr = 4.43
L3	PEC	0
Prepreg	NP155F-7628-RC49%	0.21040	εr = 4.40
L4	PEC	0

OSH Park 4-Layer PCB

Layer	Material	Thickness (mm)	Parameters
L1	PEC	0
Prepreg	FR408HR-2x2113-RC57%	0.1999	εr = 3.61
L2	PEC	0
Core	FR408HR-Core	0.9906	εr = 3.87
L3	PEC	0
Prepreg	FR408HR-2x2113-RC57%	0.1999	εr = 3.61
L4	PEC	0