Top Products

  Ethernet LAN transformers—also known as Ethernet isolation transformers or LAN magnetics—are critical components in 10/100/1000Base-T and PoE Ethernet interfaces. However, many engineers and buyers struggle to correctly interpret LAN transformer electrical specifications such as OCL, insertion loss, return loss, crosstalk, DCMR, and isolation voltage.   This guide explains what each LAN transformer electrical parameter really means, how it is measured, and why it matters in real Ethernet and PoE designs, helping you select the right magnetics with confidence.     ★ LAN Transformer Electrical Specifications – Summary Table   Parameter Typical Value Test Condition What It Indicates Turns Ratio 1CT:1CT (TX/RX) — Impedance matching between PHY and twisted-pair cable OCL (Open Circuit Inductance) ≥ 350 µH 100 kHz, 100 mV, 8 mA DC bias Low-frequency signal stability and EMI suppression Insertion Loss ≤ -1.2 dB 1–100 MHz Signal attenuation across Ethernet frequency band Return Loss ≥ -16 dB @1–30 MHz Differential mode Impedance matching quality Crosstalk ≥ -45 dB @30 MHz Adjacent pairs Pair-to-pair interference isolation DCMR ≥ -43 dB @30 MHz Differential-to-common mode Common-mode noise rejection Isolation Voltage 1500 Vrms 60 sec Safety isolation between line and device Operating Temperature 0°C to 70°C Ambient Environmental reliability       ★ What Is a LAN Transformer and Why Specs Matter       A LAN transformer provides:   Galvanic isolation between Ethernet PHY and cable Impedance matching for twisted-pair transmission Common-mode noise suppression PoE DC power coupling through center taps (for PoE designs)   Incorrect interpretation of electrical specifications can lead to:   Link instability Packet loss EMI/EMC failures PoE malfunction or overheating   Understanding these parameters is therefore essential for hardware engineers, system designers, and procurement teams.     ① Turns Ratio (Primary : Secondary)   What It Means The turns ratio defines the voltage relationship between the PHY side and the cable side of the transformer.   Typical examples:   1:1 (1CT:1CT) for 10/100Base-T Center Tap (CT) used for biasing and PoE power injection   Why Turns Ratio Matters   Ethernet PHYs are designed around a 1:1 impedance environment Incorrect ratios cause: Impedance mismatch Increased return loss PHY transmit amplitude violations   Engineering Insight   For 10/100Base-T and PoE, a 1:1 turns ratio with center taps is the industry standard and safest choice.     ② Open Circuit Inductance (OCL)   Definition OCL (Open Circuit Inductance) measures the transformer's inductance with the secondary open, typically at:   100 kHz Low AC voltage With specified DC bias (important for PoE)   What OCL Represents   OCL indicates how well the transformer:   Blocks low-frequency components Prevents baseline wander Maintains signal integrity under DC bias   Why DC Bias Matters in PoE   PoE injects DC current through the center taps, which pushes the magnetic core toward saturation. A PoE-rated LAN transformer must maintain sufficient inductance under DC bias, not just at zero current.   Typical Engineering Benchmarks OCL Value Interpretation < 200 µH Risk of low-frequency distortion 250–300 µH Marginal ≥ 350 µH PoE-capable, robust design     ③ Insertion Loss   Definition Insertion loss measures how much signal power is lost when passing through the transformer, expressed in dB.   Why It Matters High insertion loss results in:   Reduced eye opening Lower signal-to-noise ratio Shorter maximum cable length   Industry Expectations   For 10/100Base-T:   ≤ −1.5 dB: Acceptable ≤ −1.2 dB: Very good ≤ −1.0 dB: High-performance   Low insertion loss is essential for stable links and margin against poor cabling.     ④ Return Loss   Definition Return loss quantifies signal reflections caused by impedance mismatch. Higher absolute values (more negative dB) mean less reflection.   Why Return loss Matters Excessive reflections:   Distort transmitted signals Cause self-interference at the PHY Increase bit error rate (BER)   Frequency Dependency Return loss requirements relax slightly at higher frequencies, consistent with IEEE 802.3 templates.   Engineering Interpretation Good return loss indicates:   Proper impedance matching Transformer + PCB layout compatibility Better tolerance to manufacturing variation     ⑤ Crosstalk   Definition Crosstalk measures how much signal from one differential pair couples into another.   Why LAN Magnetics Crosstalk Matters Ethernet uses multiple differential pairs. High crosstalk leads to:   Increased noise floor Data corruption EMI failures   Typical Reference Values Crosstalk @ 100 MHz Evaluation −30 dB Marginal −35 dB Good −40 dB or better Excellent   Strong crosstalk isolation is especially important in compact PoE designs.     ⑥ Differential-to-Common Mode Rejection (DCMR)   Definition DCMR measures how effectively the transformer prevents differential signals from converting into common-mode noise (and vice versa).   Why DCMR Is Critical for PoE   PoE systems introduce:   DC current Switching regulator noise Ground potential differences   Poor DCMR leads to:   EMI issues Link instability Video/audio artifacts in IP devices   Engineering Benchmark   ≥ −30 dB at 100 MHz is considered strong Higher DCMR = better EMC performance     ⑦ Isolation Voltage (Hi-Pot Rating)   Definition Isolation voltage specifies the maximum AC voltage the transformer can withstand between primary and secondary without breakdown.   Typical values: 1000 Vrms (low) 1500 Vrms (standard Ethernet) 2250 Vrms (industrial/high-reliability)   Why Hi-Pot Matters   User safety Surge and lightning protection Regulatory compliance (UL, IEC)   For most Ethernet and PoE equipment, 1500 Vrms meets IEEE and UL expectations.     ⑧ Operating Temperature Range   Definition Specifies the ambient temperature range where electrical performance is guaranteed.   Typical classes: 0°C to 70°C – Commercial / SOHO / VoIP −40°C to +85°C – Industrial −40°C to +105°C – Harsh environments   Engineering Consideration Higher temperature ratings generally imply:   Better core material Higher cost Improved long-term reliability     ★ How to Use These Specs When Selecting a LAN Transformer       When comparing LAN transformers, always evaluate parameters together, not individually:   OCL + DC bias → PoE capability Insertion loss + return loss → signal integrity margin Crosstalk + DCMR → EMI robustness Isolation voltage → safety and compliance Temperature range → application suitability     { "@context": "https://schema.org", "@type": "FAQPage", "mainEntity": [{ "@type": "Question", "name": "What is OCL in a LAN transformer?", "acceptedAnswer": { "@type": "Answer", "text": "OCL (Open Circuit Inductance) measures the transformer's low-frequency inductance and its ability to suppress EMI while maintaining Ethernet signal integrity." } }] } ★ LAN Transformer Electrical Specifications FAQs   Q1: What is OCL in a LAN transformer? OCL (Open Circuit Inductance) measures the transformer’s ability to maintain signal integrity at low frequencies. Higher OCL values improve EMI suppression and help meet IEEE 802.3 return loss requirements.   Q2: Why is turns ratio important in Ethernet magnetics? The turns ratio ensures impedance matching between the Ethernet PHY and the twisted-pair cable. A 1:1 ratio is standard for 10/100Base-T Ethernet to minimize signal reflection and distortion.   Q3: What does insertion loss mean in LAN transformers? Insertion loss represents how much signal power is lost when passing through the transformer. Lower insertion loss ensures better signal quality, especially across the 1–100 MHz Ethernet bandwidth.   Q4: How does return loss affect Ethernet performance? Return loss indicates impedance mismatch in the transmission path. Poor return loss causes signal reflections, increasing bit error rates and link instability in Ethernet systems.   Q5: What is DCMR and why is it critical for PoE applications? DCMR (Differential to Common Mode Rejection) measures how well a transformer suppresses common-mode noise. High DCMR is essential for PoE systems where power and data share the same cable.   Q6: What isolation voltage is required for PoE LAN transformers? Most PoE LAN transformers require at least 1500 Vrms isolation to protect equipment and users from surge voltages and comply with safety standards such as UL and IEEE 802.3.  

  LAN magnetics, also known as Ethernet transformers or network isolation magnetics, are essential components in wired Ethernet interfaces. They provide galvanic isolation, impedance matching, common-mode noise suppression, and support for Power over Ethernet (PoE). Proper selection and validation of LAN magnetics directly impact signal integrity, electromagnetic compatibility (EMC), system safety, and long-term reliability.   This engineering-focused guide presents a comprehensive framework for understanding LAN magnetics design principles, electrical specifications, PoE performance, EMI behavior, and validation methodologies. It is intended for hardware engineers, system architects, and technical procurement teams involved in Ethernet interface design across enterprise, industrial, and mission-critical applications.       ◆ Ethernet Speed And Standards Support     Matching Magnetics To PHY And Link Requirements   LAN magnetics must be carefully matched to the targeted Ethernet physical layer (PHY) and supported data rate. Common standards include:   10BASE-T (10 Mbps) 100BASE-TX (100 Mbps) 1000BASE-T (1 Gbps) 2.5GBASE-T and 5GBASE-T (Multi-Gigabit Ethernet) 10GBASE-T (10 Gbps)   Signal Bandwidth Considerations For Multi-Gigabit Ethernet   Multi-gigabit Ethernet extends signal bandwidth beyond 100 MHz. For 2.5G, 5G, and 10G links, magnetics must maintain low insertion loss, flat frequency response, and minimal phase distortion up to 200 MHz or higher to preserve eye opening and jitter margin.     ◆ Isolation Voltage (Hipot) And Insulation Grade     1. Industry Baseline Requirements The baseline dielectric withstand voltage requirement for standard Ethernet ports is ≥1500 Vrms for 60 seconds, ensuring user safety and regulatory compliance.   2. Industrial And High-Reliability Isolation Levels Industrial, outdoor, and infrastructure equipment typically require reinforced insulation of 2250–3000 Vrms, while railway, energy, and medical systems may require 4000–6000 Vrms isolation to meet elevated safety and reliability requirements.   3. Hipot Test Methods And Acceptance Criteria Hipot testing is performed at 50–60 Hz for 60 seconds. No dielectric breakdown or excessive leakage current is permitted under IEC 62368-1 test conditions.   4. Typical Isolation Ratings In LAN Transformers   Application Category Isolation Voltage Rating Test Duration Applicable Standards Typical Use Cases Standard Commercial Ethernet 1500 Vrms 60 s IEEE 802.3, IEC 62368-1 Enterprise switches, routers, IP phones Enhanced Insulation Ethernet 2250–3000 Vrms 60 s IEC 62368-1, UL 62368-1 Industrial Ethernet, PoE cameras, outdoor APs High-Reliability Industrial Ethernet 4000–6000 Vrms 60 s IEC 60950-1, IEC 62368-1, EN 50155 Railway systems, power substations, automation control Medical and Safety-Critical Ethernet ≥4000 Vrms 60 s IEC 60601-1 Medical imaging, patient monitoring Outdoor and Harsh Environment Networking 3000–6000 Vrms 60 s IEC 62368-1, IEC 61010-1 Surveillance, transportation, roadside systems     Engineering Notes   1500 Vrms for 60 seconds is the baseline isolation requirement for standard Ethernet ports. ≥3000 Vrms is commonly required in industrial and outdoor systems to improve surge and transient robustness. 4000–6000 Vrms isolation is typically mandated in railway, medical, and critical infrastructure environments. Higher isolation ratings require larger creepage and clearance distances, which directly impact transformer size and PCB layout.     ◆ PoE Compatibility And DC Current Ratings     IEEE 802.3af, 802.3at, And 802.3bt Power Classes Power over Ethernet (PoE) enables power delivery and data transmission through twisted-pair cabling. Supported standards include IEEE 802.3af (PoE), 802.3at (PoE+), and 802.3bt (PoE++ Type 3 and Type 4).     Standard Common Name PoE Type Max Power at PSE Max Power at PD Nominal Voltage Range Max DC Current per Pair Set Pairs Used Typical Applications IEEE 802.3af PoE Type 1 15.4 W 12.95 W 44–57 V 350 mA 2 pairs IP phones, basic IP cameras IEEE 802.3at PoE+ Type 2 30.0 W 25.5 W 50–57 V 600 mA 2 pairs Wi-Fi APs, PTZ cameras IEEE 802.3bt PoE++ Type 3 60.0 W 51.0 W 50–57 V 600 mA 4 pairs Multi-radio APs, thin clients IEEE 802.3bt PoE++ Type 4 90.0 W 71.3 W 50–57 V 960 mA 4 pairs LED lighting, digital signage   Center-Tap Current Capability And Thermal Constraints PoE injects DC current through transformer center taps. Depending on PoE class, magnetics must safely handle 350 mA to nearly 1 A per pair set without entering saturation or excessive thermal rise.   Transformer Saturation And PoE Reliability Insufficient saturation current (Isat) leads to inductance collapse, degraded EMI suppression, increased insertion loss, and accelerated thermal stress. High-power PoE systems require optimized core geometry and low-loss magnetic materials.     ◆ Key Magnetic And Electrical Parameters   ● Magnetizing Inductance (Lm) Typical gigabit designs require 350–500 µH measured at 100 kHz. Adequate Lm ensures low-frequency signal coupling and baseline stability.   ● Leakage Inductance Lower leakage inductance improves high-frequency coupling and reduces waveform distortion. Values below 0.3 µH are generally preferred.   ● Turns Ratio And Mutual Coupling Ethernet transformers typically use a 1:1 turns ratio with tightly coupled windings to minimize differential-mode distortion and maintain impedance balance.   ● DC Resistance (DCR) Lower DCR reduces conduction loss and thermal rise under PoE load. Typical values range from 0.3 to 1.2 Ω per winding.   ● Saturation Current (Isat) Isat defines the DC current level before inductance collapse. PoE++ designs often require Isat exceeding 1 A.       ◆ Signal Integrity Metrics And S-Parameter Requirements   ▶ Insertion Loss Across The Operating Band Insertion loss directly reflects the signal attenuation introduced by the magnetic structure and inter-winding parasitics. For 1000BASE-T applications, insertion loss should remain below 1.0 dB across 1–100 MHz, while for 2.5G, 5G, and 10GBASE-T, loss should typically remain below 2.0 dB up to 200 MHz or higher.   Excessive insertion loss reduces eye height, increases bit error rate (BER), and degrades link margin, particularly in long cable runs and high-temperature environments. Engineers should always evaluate insertion loss using de-embedded S-parameter measurements under controlled impedance conditions.   ▶ Return Loss And Impedance Matching Return loss quantifies impedance mismatch between the magnetics and the Ethernet channel. Values better than –16 dB across the operating frequency band are typically required for reliable gigabit and multi-gigabit links.   Poor impedance matching leads to signal reflections, eye closure, baseline wander, and increased jitter. For 10GBASE-T systems, stricter return loss targets (often better than –18 dB) are recommended due to the tighter signal margin.   ▶ Crosstalk Performance (NEXT And FEXT)   Near-end crosstalk (NEXT) and far-end crosstalk (FEXT) represent unwanted signal coupling between adjacent differential pairs. Low crosstalk preserves signal margin, minimizes timing skew, and improves overall electromagnetic compatibility.   High-quality LAN magnetics employ tightly controlled winding geometry and shielding structures to minimize pair-to-pair coupling. Crosstalk degradation is particularly critical in multi-gigabit and high-density PCB layouts.       ▶ Common-Mode Choke (CMC) Characteristics And EMI Control     Frequency Response And Impedance Curves The common-mode choke (CMC) is essential for suppressing broadband electromagnetic interference (EMI) generated by high-speed differential signaling. CMC impedance typically increases from tens of ohms at 1 MHz to several kilo-ohms above 100 MHz, providing effective attenuation of high-frequency common-mode noise.   A well-designed impedance profile ensures effective EMI suppression without introducing excessive differential-mode insertion loss.   DC Bias Effects On CMC Performance In PoE-enabled systems, DC current flowing through the choke core introduces magnetic bias that reduces effective permeability and impedance. This phenomenon becomes increasingly significant in PoE+, PoE++, and high-power Type 4 applications.   To maintain EMI suppression under DC bias, designers must select larger core geometries, optimized ferrite materials, and carefully balanced winding structures capable of sustaining high DC current without saturation.     ◆ ESD, Surge, And Lightning Immunity   ♦ IEC 61000-4-2 ESD Requirements Typical Ethernet interfaces require ±8 kV contact discharge and ±15 kV air discharge immunity according to IEC 61000-4-2. While magnetics provide galvanic isolation, dedicated transient voltage suppression (TVS) diodes are usually required to clamp fast ESD transients.   ♦ IEC 61000-4-5 Surge And Lightning Protection Industrial, outdoor, and infrastructure equipment must often withstand 1–4 kV surge pulses as defined by IEC 61000-4-5. Surge protection requires a coordinated design strategy combining gas discharge tubes (GDTs), TVS diodes, current-limiting resistors, and optimized grounding structures.   LAN magnetics primarily provide isolation and noise filtering but must be validated under surge stress to ensure insulation integrity and long-term reliability.     ◆ Thermal, Temperature, And Environmental Requirements   Operating Temperature Ranges   Commercial-grade: 0°C to +70°C Industrial-grade: –40°C to +85°C Extended industrial: –40°C to +125°C   Extended temperature designs require specialized core materials, high-temperature insulation systems, and low-loss winding conductors to prevent thermal drift and performance degradation.   PoE-Induced Thermal Rise PoE introduces significant DC copper loss and core loss, especially under high-power operation. Thermal modeling must account for conduction loss, magnetic hysteresis loss, ambient airflow, PCB copper spreading, and enclosure ventilation.   Excessive temperature rise accelerates insulation aging, increases insertion loss, and may cause long-term reliability failures. A thermal rise margin below 40°C at full PoE load is commonly targeted in industrial designs.     ◆ Mechanical, Packaging, And PCB Footprint Considerations     MagJack Versus Discrete Magnetics Integrated MagJack connectors combine RJ45 jacks and magnetics into a single package, simplifying assembly and reducing PCB area. However, discrete magnetics offer superior flexibility for EMI optimization, impedance tuning, and thermal management, making them preferable for high-performance, industrial, and multi-gigabit designs.   Package Types: SMD And Through-Hole Surface-mount (SMD) magnetics support automated assembly, compact PCB layouts, and high-volume manufacturing. Through-hole packages provide enhanced mechanical robustness and higher creepage distances, often favored in industrial and vibration-prone environments.   Mechanical parameters such as package height, pin pitch, footprint orientation, and shield grounding configuration must be aligned with PCB layout constraints and enclosure design requirements.     ◆ Test Conditions And Measurement Methods   1. Inductance And Leakage Measurement Techniques Measurements are typically conducted at 100 kHz using calibrated LCR meters under low excitation voltage.   2. Hipot Testing Procedures Dielectric tests are performed at rated voltage for 60 seconds in controlled environments.   3. S-Parameter Measurement Setup Vector network analyzers with de-embedded fixtures ensure accurate high-frequency characterization.     ◆ Practical Lab Validation Procedure   Incoming Inspection And Mechanical Verification Dimensional, marking, and solderability inspection ensures production consistency.   Electrical And Signal Integrity Testing Includes impedance, insertion loss, return loss, and crosstalk validation.   PoE Stress And Thermal Validation Extended DC current testing validates thermal margin and saturation stability.     ◆ Acceptance Checklist For Design And Procurement   Standards compliance (IEEE, IEC) Electrical performance margin PoE current capability Thermal reliability EMI suppression effectiveness Mechanical compatibility     ◆ Common Failure Modes And Engineering Pitfalls   Core saturation under PoE load Insufficient isolation rating High insertion loss at high frequency Poor EMI suppression     ◆ Frequently Asked Questions About LAN Magnetics   Q1: Do Multi-Gigabit Designs Require Special Magnetics? Yes. Multi-gigabit Ethernet requires wider bandwidth, lower insertion loss, and tighter impedance control.   Q2: Is PoE Compatibility Guaranteed By Default? No. DC current rating, saturation current (Isat), and thermal behavior must be explicitly validated.   Q3: Can Magnetics Alone Provide Surge Protection? No. External surge protection components are required.   Q4: What Magnetizing Inductance Is Required For Gigabit Ethernet? 350–500 µH measured at 100 kHz is typical.   Q5: How Does PoE Current Affect Transformer Saturation? DC bias reduces magnetic permeability, potentially driving the core into saturation and increasing distortion and thermal stress.   Q6: Is Higher Isolation Voltage Always Better? No. Higher ratings increase size, cost, and PCB spacing requirements and should match system safety needs.   Q7: Are Integrated MagJacks Equivalent To Discrete Magnetics? They are electrically similar, but discrete magnetics offer greater layout and EMI optimization flexibility.   Q8: What Insertion Loss Levels Are Acceptable? Less than 1 dB up to 100 MHz for gigabit and less than 2 dB up to 200 MHz for multi-gigabit designs.   Q9: Can PoE Magnetics Be Used In Non-PoE Systems? Yes. They are fully backward compatible.   Q10: What Layout Errors Most Often Degrade Performance? Asymmetric routing, poor impedance control, excessive stubs, and improper grounding.     ◆ Conclusion     LAN magnetics are foundational components in Ethernet interface design, directly influencing signal integrity, electrical safety, EMC compliance, and long-term system reliability. Their performance affects not only data transmission quality but also the robustness of PoE power delivery, surge immunity, and thermal stability.   From matching transformer bandwidth to PHY requirements, verifying isolation ratings and PoE current capability, to validating magnetic parameters and EMC behavior, engineers must evaluate LAN magnetics from a system-level perspective rather than as simple passive components. A disciplined validation workflow significantly reduces field failures and costly redesign cycles.   As Ethernet continues to evolve toward multi-gigabit speeds and higher PoE power levels, careful component selection, supported by transparent datasheets, rigorous testing methodologies, and sound layout practices, remains essential for building reliable, standards-compliant network equipment across enterprise, industrial, and mission-critical applications.  

  ★ Introduction: Why Ethernet Connector Choice Matters for Raspberry Pi 4   The Raspberry Pi 4 Model B represents a major leap forward compared to previous generations. With a faster CPU, true Gigabit Ethernet, and expanded use cases ranging from industrial gateways to edge computing and media servers, network performance has become a critical design factor rather than an afterthought.   While many developers focus on software optimization, the Ethernet connector and integrated magnetics (MagJack) play a decisive role in signal integrity, PoE reliability, EMI compliance, and long-term stability. For engineers looking to replace or source an alternative to A70-112-331N126, LINK-PP’s LPJG0926HENL has emerged as a proven and cost-effective solution.   This article provides a deep technical breakdown of LPJG0926HENL as an alternative MagJack for Raspberry Pi 4 applications, covering electrical performance, mechanical compatibility, PoE considerations, PCB footprint guidelines, and installation best practices.   What You Will Learn from This Guide   By reading this article, you will be able to:   Understand why LPJG0926HENL is commonly used as an alternative to A70-112-331N126 Verify compatibility with Raspberry Pi 4 Ethernet requirements Compare electrical, mechanical, and PoE-related characteristics Avoid common PCB footprint and soldering mistakes Make informed sourcing decisions for production-scale projects     ★ Understanding Raspberry Pi 4 Ethernet Requirements   The Raspberry Pi 4 Model B features a true Gigabit Ethernet interface (1000BASE-T), no longer limited by the USB 2.0 bottleneck found in earlier models. This improvement introduces stricter requirements for the Ethernet connector and magnetics, including:   Stable 100/1000 Mbps auto-negotiation Low insertion loss and controlled impedance Proper common-mode noise suppression Compatibility with PoE HAT designs Reliable LED status indication for debugging   Any RJ45 MagJack used on a Raspberry Pi 4–based design must meet these baseline expectations to avoid packet loss, EMI issues, or intermittent link failures.     ★ Overview of LPJG0926HENL       LPJG0926HENL is a 1×1 single-port RJ45 connector with integrated magnetics, designed for Gigabit Ethernet applications. It is widely deployed in single-board computers (SBCs), embedded controllers, and industrial networking devices.   Key Highlights   Supports 100/1000BASE-T Ethernet Integrated magnetics for signal isolation PoE / PoE+ capable design Through-Hole Technology (THT) mounting Dual LED indicators (Green / Yellow) Compact footprint suitable for SBC layouts   These features align closely with the functional profile of A70-112-331N126, making LPJG0926HENL a strong drop-in or near-drop-in replacement candidate.     ★ LPJG0926HENL vs. A70-112-331N126: Functional Comparison   Feature LPJG0926HENL A70-112-331N126 Ethernet Speed 10/100/1000BASE-T 10/100/1000BASE-T Port Configuration 1×1 Single Port 1×1 Single Port Magnetics Integrated Integrated PoE Support Yes Yes LED Indicators Green (Left) / Yellow (Right) Green / Yellow Mounting THT THT Target Applications SBCs, Routers, IoT SBCs, Industrial     From a system-level perspective, both connectors serve the same purpose. Engineers typically choose LPJG0926HENL for cost efficiency, supply stability, and wide adoption in Raspberry Pi–style designs.     ★ Electrical Performance and Signal Integrity       For Gigabit Ethernet, magnetics quality is essential. LPJG0926HENL integrates:   Isolation transformers compliant with IEEE 802.3 requirements Balanced differential pairs for reduced crosstalk Optimized return loss and insertion loss performance   These characteristics help ensure:   Stable Gigabit throughput Reduced EMI emissions Improved compatibility with long cable runs   In real-world Raspberry Pi 4 deployments, LPJG0926HENL supports smooth data transfer for streaming, file servers, and network-attached applications without link instability.     ★ PoE and Power Delivery Considerations   Many Raspberry Pi 4 projects rely on Power over Ethernet (PoE) to simplify cabling and deployment, especially in industrial or ceiling-mounted installations.   LPJG0926HENL is designed to support PoE and PoE+ applications when paired with an appropriate PoE controller and power circuitry. Key design notes include:   Ensure correct center-tap routing on the magnetics Follow IEEE 802.3af/at power budget guidelines Use adequate PCB copper thickness for power paths Consider thermal dissipation in enclosed housings   When implemented correctly, LPJG0926HENL enables stable power delivery and data transmission over a single Ethernet cable.     ★ LED Indicators: Practical Diagnostics for Developers   LPJG0926HENL includes two integrated LEDs:   Left LED (Green) – Link status Right LED (Yellow) – Activity or speed indication   These LEDs are especially valuable during:   Initial board bring-up Network debugging Field diagnostics   For Raspberry Pi–based devices deployed in remote or industrial environments, visual status feedback significantly reduces troubleshooting time.     ★ Mechanical Design and PCB Footprint Guidelines       Although LPJG0926HENL is often used as an alternative to A70-112-331N126, engineers should never assume identical footprints without verification.   Critical Checks Before Replacement   1. Pinout mapping Confirm Ethernet pairs, LED pins, and shield grounding pins.   2. Pad spacing and hole diameter Verify THT hole size tolerance for wave or selective soldering.   3. Shield tabs and grounding Ensure proper chassis grounding to maintain EMI performance.   4. Connector orientation Most designs use tab-down orientation, but confirm mechanical drawings.   Failing to validate these parameters may result in assembly issues or EMI non-compliance.     ★ Installation and Soldering Best Practices (THT)   LPJG0926HENL uses Through-Hole Technology, which offers strong mechanical retention—ideal for Ethernet cables frequently being plugged and unplugged.     Recommended Practices   Use reinforced pads for shield pins Maintain consistent solder fillets for signal pins Avoid excessive solder that may wick into the connector Clean flux residue to prevent corrosion Inspect solder joints for voids or cold joints   Proper soldering ensures long-term reliability, especially in vibration-prone environments.     ★ Typical Applications Beyond Raspberry Pi 4       While frequently associated with Raspberry Pi boards, LPJG0926HENL is also used in:   Industrial Ethernet controllers Networked sensors and IoT gateways Embedded Linux SBCs Smart home hubs Edge computing devices   This wide adoption further confirms its maturity and reliability as a Gigabit Ethernet MagJack.     ★ Why Engineers Choose LPJG0926HENL   From both a technical and commercial standpoint, LPJG0926HENL offers several advantages:   Proven compatibility with SBC Ethernet designs Competitive pricing for volume production Stable supply chain and shorter lead times Clear documentation and footprint availability Strong field performance in PoE environments   These factors make it a practical alternative for engineers seeking flexibility without sacrificing performance.     ★ Frequently Asked Questions (FAQs)   Q1:Can LPJG0926HENL directly replace A70-112-331N126 on a Raspberry Pi 4 PCB? In many designs, yes. However, engineers should always confirm pinout and mechanical drawings before finalizing the PCB.     Q2:Does LPJG0926HENL support PoE+? Yes, when used with a compliant PoE power circuit and proper PCB layout.     Q3:Are the LED functions configurable? LED behavior depends on the Ethernet PHY and system design. The connector supports standard link/activity signaling.     Q4:Is LPJG0926HENL suitable for industrial environments? Yes. Its THT mounting and integrated shield provide mechanical robustness and EMI protection.     ★ Conclusion: A Smart Alternative for Modern Ethernet Designs   As Raspberry Pi 4 continues to power more advanced and demanding applications, choosing the right Ethernet MagJack becomes increasingly important. LPJG0926HENL offers a well-balanced combination of Gigabit performance, PoE capability, mechanical robustness, and cost efficiency, making it a strong alternative to A70-112-331N126.   For engineers designing Raspberry Pi–based systems or compatible SBCs, LPJG0926HENL represents a reliable, production-ready choice that aligns with both technical and commercial requirements.