Learn about R-5775R embedded resistor PCB聽materials in Panasonic MEGTRON鈥�6R, including buried resistor foil specs, stackup tips, electrical/thermal properties, and design guidance for high-speed multilayer boards.
Understanding R–5775R embedded resistor PCB material is essential for advanced PCB engineers working on multilayer, high-speed, and high-density designs. 笔补苍补蝉辞苍颈肠鈥檚 MEGTRON鈥�6 family includes the R-5775(R) variant specifically engineered to integrate embedded resistor copper foil into the board core 鈥� enabling new options for termination, signal integrity improvements, and layout efficiency in demanding applications.
This technical guide breaks down the material properties, how embedded resistors work in practice, PCB design implications, and real-world engineering tips.
Table of Contents
What Is R–5775R embedded resistor PCB Material?
MEGTRON鈥�6R in the MEGTRON Family
Embedded Resistors: Materials and Technology
Key Material Properties of R-5775(R)
Electrical Characteristics (Buried Resistor Copper Foil)
Mechanical and Thermal Properties
Practical PCB Stackup Considerations
Typical Applications and Design Benefits
Material Comparison With Non-Resistor Laminates
Quick Reference Tables
seful Resources and Downloads
FAQs for Engineers
Conclusion
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1. What Is R–5775R Embedded Resistor PCB Material?
The term R–5775R embedded resistor PCB refers to a Panasonic MEGTRON鈥�6R substrate that integrates buried resistor copper foil into the laminate stackup. Unlike conventional laminates that only provide the dielectric and standard copper, this material includes a special resistive foil layer built into the laminate structure, enabling designers to embed resistor networks directly within the PCB core.
This integration is impactful for high-speed, high-density boards 鈥� particularly where many termination resistors are needed (e.g., controlled impedance buses) or where board area is at a premium.
Embedding resistors as part of the internal copper foil layer eliminates the need for discrete resistors on the surface, reducing solder joints and improving long-term reliability.
2. MEGTRON鈥�6R in the MEGTRON Family
笔补苍补蝉辞苍颈肠鈥檚 MEGTRON series of PCB materials are designed for ultra–low signal loss, high heat resistance, and multi–layer board performance. The MEGTRON鈥�6 subfamily covers several laminate options tailored for specific performance and processing goals:
| Variant | Specialty | Notes |
| R–5775(N) | Low Dk glass | Low loss, high SI focus |
| R–5775(S) | Standard glass + embedded resistor foil | Balanced performance + resistor integration |
| R–5775(R) | Embedded resistor PCB laminate | Embedded resistive foil for passive integration |
| R-5775(K), R-5775(G) | Standard glass cloth variants | Conventional multilayer laminates |
The R–5775R embedded resistor PCB option extends the base MEGTRON鈥�6 properties by adding the capability to embed resistors directly in the dielectric-copper interface.
3. Embedded Resistors: Materials and Technology
Embedded resistors in PCBs are a mature passive integration technique widely used in high-performance and high-reliability circuits. Instead of mounting discrete resistors on the external surface, the resistive material is incorporated into an internal layer of the PCB. This is typically done by bonding a thin resistive foil to the dielectric, then patterning it during etch.
How Embedded Resistors Work
The fundamental principle:
R = (L / W) 脳 搁鈧�
Where:
R = resistance (惟)
L = length of the resistive trace
W = width of that trace
搁鈧� = sheet resistivity of the embedded resistive material (惟/sq)
This approach allows precise resistance values based on geometry and foil resistivity. Typical embedded resistor technologies use thin-film alloys or specialized resistive copper foils laminated into the core.
4. Key Material Properties of R–5775(R)
According to 笔补苍补蝉辞苍颈肠鈥檚 MEGTRON6 series documentation, R–5775(R) variant uses buried resistor copper foil combined with core laminate properties similar to other MEGTRON鈥�6 materials.
Typical Structural Overview
| Layer Component | Function |
| Dielectric Core | Standard MEGTRON鈥�6 laminate base |
| Standard Copper Foil | Conventional conductor layers |
| Buried Resistor Copper Foil | Resistive layer laminated into internal PCB plane |
| Prepreg | Insulating adhesive between cores |
Buried resistor copper foil is typically thinner (鈮�1/2 oz, ~18鈥祄) to enable fine patterning and preserve layer count.
5. Electrical Characteristics (Buried Resistor Copper Foil)
Embedded resistor foil incorporated into the PCB allows pre-defined resistor networks to be formed during the etch process. 笔补苍补蝉辞苍颈肠鈥檚 documentation notes available sheet resistances typically include:
| Sheet Resistance | Typical Value | Notes |
| 词25鈥�/蝉辩 | 23.7鈥�26.2鈥� | Coarse resistor networks |
| 词50鈥�/蝉辩 | 47.5鈥�52.5鈥� | Common for impedance matching |
| 词100鈥�/蝉辩 | 95.0鈥�105鈥� | Higher-value embedded terminations |
These resistive values allow designers to implement line termination, pull-ups, or other network structures without discrete parts, improving signal integrity and saving board space.
6. Mechanical and Thermal Properties
R–5775R embedded resistor PCB retains the MEGTRON鈥�6 family鈥檚 high thermal and mechanical robustness, including:
| Property | Typical Value | Test |
| Glass Transition Temp (Tg) | 词185鈥癈 | DSC |
| Z-Axis CTE (below Tg) | 词45鈥痯辫尘/掳颁 | IPC-TM-650 |
| Z-Axis CTE (above Tg) | 词260鈥痯辫尘/掳颁 | IPC-TM-650 |
| T288 (with Cu) | &驳迟;120鈥痬颈苍 | IPC-TM-650 |
| Moisture Absorption | 词0.14鈥�% | IPC-TM-650 |
| Peel Strength | 0.8鈥痥狈/尘 | H-VLP Copper |
The embedded resistor foil does not significantly alter the base laminate鈥檚 thermal behavior, but engineers should coordinate resistor foil handling with the PCB fabricator for optimal lamination and plating results.
7. Practical PCB Stackup Considerations
Designing a stackup with R–5775R embedded resistor PCB requires coordination between engineering and the PCB fabricator.
Where to Place Embedded Resistors
Inner layers closest to signal planes: keep resistor nets proximate to the signals they terminate for best SI/PI.
Inner layers adjacent to ground return: helps reduce EMI and maintain controlled impedance.
Keep embedded resistive patterns predictable: avoid complex routing over the resistive foil unless intentionally designed.
Simulation and Impedance Control
When resistive material is adjacent to signal layers, it can slightly affect characteristic impedance due to fringe fields and dielectric loading. Best practice:
Use field-solver tools that account for multilayer trace structure with embedded resistive foil.
Validate controlled impedance with test coupons.
Collaboration With Fabricator
Discuss early:
Foil pattern restrictions (minimum width/space)
Plan for resistor trimming/adjustment if needed
Layer stack tolerances with embedded foil
These steps improve manufacturing yield and ensure embedded resistor placement performs as intended.
8. Typical Applications and Design Benefits
Using R–5775R embedded resistor PCB delivers design benefits and enables compact layouts:
| Application | Benefit from Embedded Resistors |
| High-speed digital boards | Fewer discrete terminations, improved SI |
| Networking equipment | Reduced routing area, compact stackups |
| RF and wireless systems | Minimized parasitic inductance |
| Aerospace/Defense boards | Improved reliability, fewer solder joints |
| High-density HDI PCBs | Space efficiency and reduced BOM cost |
Embedded resistors deliver tangible advantages where board complexity and performance intersect.
9. Material Comparison With Non–Resistor Laminates
| Material Variant | Embedded Resistive Layer | Best Use Case |
| R-5775(N) | No | Ultra-low loss SI |
| R-5775(S) | Yes | Balanced high speed + resistor |
| R–5775(R) | Yes, optimized for embedded resistor PCB | Designs needing integrated resistors |
| R-5775(K) | No | Standard multilayer boards |
The R-5775R variant brings embedded passives inside the PCB without sacrificing core electrical performance of the MEGTRON鈥�6 class.
10. Quick Reference Tables
Buried Resistor Copper Foil Options
| Sheet Resistivity | Typical Usage |
| 25鈥�/蝉辩 | Termination networks |
| 50鈥�/蝉辩 | General resistive loads |
| 100鈥�/蝉辩 | Higher-value embedded passives |
MEGTRON鈥�6R Core Properties
| Property | Typical Value |
| Dk (鈮�12鈥疓Hz) | ~3.4 |
| Df | ~0.004 |
| Tg | 词185鈥癈 |
| T288 (with Cu) | &驳迟;120鈥痬颈苍 |
| Z-Axis CTE | ~45 / 260鈥痯pm/掳C |
These consolidated values help engineers quickly reference core laminate performance.
11. Useful Resources and Downloads
Below are helpful documents and tools for engineers working with embedded resistor PCB materials:
Panasonic MEGTRON6 Series Catalogue (PDF) 鈥� core material details (Download from Panasonic)
Buried Resistor Copper Foil specification (PDF) 鈥� detailed resistor foil characteristics
Industry PCB material databases 鈥� parametric search by material type
Field solver stackup tools 鈥� for impedance simulation
PCBFab/Manufacture contacts 鈥� for embedded resistor build rules
Panasonic PCB manufacturing insight at 吃瓜tv: /Panasonic-pcb/
12. Engineer鈥檚 FAQs
1. What is an embedded resistor PCB and how does R–5775R support it?
Embedded resistor PCB integrates resistive elements into the internal layers of the PCB, reducing discrete components. R-5775R incorporates buried resistor copper foil into the laminate stack.
2. What resistive values are typically available with R–5775R?
笔补苍补蝉辞苍颈肠鈥檚 buried resistor copper foil is available in ~25鈥�, ~50鈥�, and ~100鈥� sheet resistivity options from the foil supplier.
3. Does embedded resistor foil affect signal quality?
When designed correctly, embedded resistors improve termination and impedance control, reducing reflections and improving SI.
4. Are there layout constraints with embedded resistor core materials?
Yes 鈥� minimum pattern widths/spaces and careful placement near relevant signals are required for best performance.
5. Where is R–5775R most beneficial?
Dense, high-speed boards with many termination or set resistor networks benefit the most from embedded resistor PCB materials like R-5775R.
13. Conclusion
For engineers working on high–performance multilayer PCBs where board real estate, signal integrity, and reliability matter, understanding R–5775R embedded resistor PCB material is critical. This variant of the MEGTRON鈥�6 family brings buried resistor integration into the heart of the board stackup, enabling compact, high-integrity layouts that outperform designs relying on surface-mount resistors.
By coupling core electrical robustness with embedded passive technology, R-5775R offers a powerful tool in the advanced PCB designer鈥檚 toolkit.
Suggested Meta Description
Learn about R–5775R embedded resistor PCB materials in Panasonic MEGTRON鈥�6R, including buried resistor foil specs, stackup tips, electrical/thermal properties, and design guidance for high-speed multilayer boards.