Realtek RTL8125BG-CG 2.5G Ethernet Controller Single Port PCIe 2.1 x1 Quad-Speed Transceiver QFN-48

RTL8125BG-CG Product Overview

The Realtek RTL8125BG-CG is a highly integrated single-port 2.5G Ethernet controller from Realtek Semiconductor, specifically designed for PCI Express applications. Housed in a QFN-48-EP (6×6mm) compact package， the RTL8125BG-CG integrates a quad-speed IEEE 802.3 compatible Media Access Controller (MAC) and a quad-speed Ethernet transceiver, supporting 10BASE-Te, 100BASE-TX, 1000BASE-T, and 2.5GBASE-T. The RTL8125BG-CG features a PCI Express 2.1 bus interface and, with advanced DSP technology and mixed-mode signal technology, offers high-speed transmission over CAT 5e UTP cable (2.5G/1000M/100M) or CAT 3 UTP cable (10M mode). The chip integrates embedded memory and supports PCI MSI/MSI-X interrupt, ACPI power management, remote wake-up (RealWoW!) , protocol offload, and IEEE 1588 Precision Time Protocol (PTP) . The RTL8125BG-CG is an ideal 2.5G Ethernet solution for desktops, notebooks, LAN on Motherboard (LOM), add-in cards, and various embedded networking applications.

RTL8125BG-CG Key Features

The RTL8125BG-CG embodies Realtek's deep expertise in high-speed Ethernet controller design. It features a PCI Express 2.1 x1 host interface with up to 5 GT/s data transfer rate. The RTL8125BG-CG offers a fully integrated single-port quad-speed MAC and PHY supporting 10BASE-Te, 100BASE-TX, 1000BASE-T, and 2.5GBASE-T. The chip supports transmission distances of up to 110 meters over CAT 5e UTP cable. The RTL8125BG-CG integrates comprehensive signal processing functions including Crossover Detection & Auto-Correction, Polarity Correction, Adaptive Equalization, Cross-talk Cancellation, Echo Cancellation, Timing Recovery, and Error Correction to ensure robust transmission and reception in various environments. The RTL8125BG-CG supports PCI MSI and MSI-X to reduce CPU interrupt overhead. It supports ACPI power management and OSPM for optimal power efficiency. The RTL8125BG-CG supports Remote Wake-up including AMD Magic Packet and Microsoft Wake-Up Frame. It also supports RealWoW! technology for remote wake-up over the Internet. The RTL8125BG-CG supports Protocol Offload for ARP (IPv4) and NS (IPv6) in D3 power state. It supports the ECMA proxy standard for sleeping hosts. The RTL8125BG-CG also supports IEEE 1588, IEEE 1588-2008, and IEEE 802.1AS Precision Time Protocol (PTP) . The chip supports PCIe L1 substate L1.1 and L1.2. The RTL8125BG-CG features an auxiliary power auto-detect function. It operates from 3.3V (I/O) and 0.95V (core) , with a maximum jumbo frame length of 16384 bytes. The RTL8125BGS-CG variant integrates a built-in switching regulator. Operating temperature range is 0℃ to +70℃.

RTL8125BG-CG Applications

With its highly integrated 2.5G Ethernet functionality and compact QFN package, the RTL8125BG-CG is widely deployed in various networking applications. The RTL8125BG-CG is a core solution for 2.5Gbps PCIe Ethernet add-in cards (NICs) . RTL8125BG-CG is suitable for desktops and notebooks with LAN on Motherboard (LOM) designs. The RTL8125BG-CG is also applicable to industrial control and embedded systems requiring high-speed wired connectivity. With support for Realtek Dragon software for bandwidth control, it is ideal for gaming PCs, workstations, and NAS devices. The RTL8125BG-CG delivers stable high-speed connectivity in both commercial and home entertainment applications.

RTL8125BG-CG Key Advantages

The RTL8125BG-CG stands out as a mature, commercially available single-port 2.5G Ethernet controller that strikes an excellent balance between high-speed performance, low power consumption, and compact packaging. Housed in a QFN-48-EP (6×6mm) compact package, it is one of the smallest 2.5G Ethernet controllers available. The RTL8125BG-CG supports 2.5GBASE-T, delivering 2.5 times faster speeds than Gigabit Ethernet over existing CAT 5e cabling. With IEEE 802.3az Energy Efficient Ethernet (EEE) support and power consumption below 700mW, RTL8125BG-CG is one of the lowest-power 2.5G Ethernet solutions on the market. The RTL8125BG-CG features RealWoW! remote wake-up, Protocol Offload, and ECMA proxy for advanced power management. It supports IEEE 1588 Precision Time Protocol (PTP) for time-sensitive industrial applications. The chip supports jumbo frames up to 16384 bytes for improved large-data transmission efficiency. With PCIe MSI/MSI-X interrupt support, CPU overhead is reduced. Realtek provides comprehensive driver support for Windows and Linux. The RTL8125BG-CG offers system integrators and OEMs a highly competitive 2.5G Ethernet connectivity solution.

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FAQs:

1 What is the RTL8125BG-CG chip
RTL8125BG-CG is a 2.5G ultra high speed Ethernet controller chip launched by Realtek which integrates both MAC and PHY layers and supports the latest 2.5GbE network standard.

2 What package and pin count does it use
RTL8125BG-CG adopts a QFN48 no lead surface mount package with 48 pins and a very compact footprint with an exposed thermal pad on the bottom suitable for high density PCBA designs.

3 What network speeds does it support
RTL8125BG-CG supports auto negotiation of 2.5Gbps, 1000Mbps, 100Mbps, and 10Mbps speeds and is fully backward compatible with traditional Gigabit and Fast Ethernet environments.

4 What host bus interface does it support
RTL8125BG-CG supports the PCI Express 2.1 or 3.0 high speed bus interface typically configured in single lane mode for high throughput data exchange with the host controller.

5 What are the operating voltage and temperature ranges
RTL8125BG-CG uses a multi voltage independent power design with a core voltage of 1 point 2 volts and interface voltage configurable to 1 point 8 volts 2 point 5 volts or 3 point 3 volts. The standard operating temperature range is from zero degrees Celsius to plus seventy degrees Celsius.

6 What application scenarios is this chip suitable for
With its 2.5G high bandwidth, RTL8125BG-CG is widely used in high performance desktop motherboards enterprise server 2.5G network cards 2.5G NAS storage devices and industrial high speed network control platforms.

7 What advanced network acceleration features does it support
RTL8125BG-CG supports the IEEE 802 point 3az Energy Efficient Ethernet standard VLAN tagging Jumbo Frames and hardware packet checksum offloading functions effectively reducing CPU utilization.

8 What are the PCB design considerations for the QFN48 package
The exposed thermal pad on the bottom must be reliably grounded to a large copper area for heat dissipation. The 2.5G Ethernet differential traces must strictly follow 100 ohm impedance matching and length control and decoupling capacitors should be placed near the power pins.

9 Does this chip require an external PHY chip for operation
No, RTL8125BG-CG does not. It integrates a complete 2.5G Ethernet PHY transceiver internally and only requires standard magnetic isolation transformers and an RJ45 connector to build a complete wired network port.

10 Which operating systems support this chip
RTL8125BG-CG has mature and comprehensive drivers fully supporting Windows 10 Windows 11 Linux and mainstream embedded operating systems for easy plug and play operation.