The **ALTG-941-R** is a high-performance, single-port Gigabit Ethernet (10/100/1000 Base-T) transformer module, commonly used in networking hardware. It serves as the physical interface between the Ethernet PHY (Physical Layer) chip and the RJ45 connector. --- ### 1. Key Technical Specifications The ALTG-941-R is designed to provide impedance matching, signal shaping, and high-voltage isolation. | Parameter | Value / Specification | | :--- | :--- | | **Type** | Magnetic Transformer Module (Discrete) | | **Speed Support** | 10/100/1000 Base-T (Gigabit Ethernet) | | **Number of Ports** | 1 Port | | **Turns Ratio** | 1:1 (Transmitter & Receiver) | | **Isolation Voltage** | 1500 Vrms (Minimum) | | **Operating Temp** | 0°C to +70°C (Standard) | | **Configuration** | Surface Mount (SMD) | --- ### 2. Internal Electronic Components Inside the ALTG-941-R housing, there are several passive components integrated into a single package: * **Isolation Transformers:** Four tiny toroidal transformers (one for each pair in a Cat5e/6 cable). They prevent DC offsets and ground loops between devices while allowing high-frequency AC data signals to pass. * **Common Mode Chokes (CMC):** These are wound on the same cores or separate cores to suppress Electromagnetic Interference (EMI) and Radio Frequency Interference (RFI). * **Termination Resistors/Capacitors:** Often included internally (depending on the specific sub-version) to provide 75-ohm termination for the "Bob Smith" circuit, which reduces common-mode noise on unused wires. --- ### 3. Functional Features The module performs three critical roles in a PCB design: 1. **Signal Integrity:** It ensures the differential signals sent by the Ethernet controller are clean and meet the IEEE 802.3ab standards. 2. **Galvanic Isolation:** It protects sensitive ICs from high-voltage spikes or static electricity (ESD) originating from the Ethernet cable. 3. **EMI Suppression:** The internal chokes filter out high-frequency noise that could cause the device to fail FCC or CE emissions testing. --- ### 4. Application Examples The ALTG-941-R is typically found in: * **Network Interface Cards (NICs):** Desktop and server LAN cards. * **Embedded Systems:** Industrial PCs and IoT gateways. * **Consumer Electronics:** Smart TVs, game consoles, and routers.