RTL8221B(I)-VB-CG - 2.5G Ethernet PHY Transceiver | Realtek
料号： RTL8221B(I)-VB-CG ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $5.8 | $5.80 |
| 10 | $5.2 | $52.00 |
| 100 | $4.65 | $465.00 |
| 500 | $4.2 | $2,100.00 |
| 1,000 | $3.8 | $3,800.00 |
| 3,000 | $3.45 | $10,350.00 |
RTL8221B(I)-VB-CG 概述
A 2.5GBASE-T Ethernet PHY (Physical Layer transceiver) is a chip that converts between the digital MAC interface and the analog twisted-pair line, enabling multi-gigabit networking over standard Cat5e cabling. The 2.5GBASE-T PHY tier sits between Gigabit Ethernet (1G) and 5GBASE-T/10GBASE-T in the Ethernet PHY hierarchy, and falls under the broader category of physical layer transceivers -> network interface ICs -> communications ICs. It is a key building block of modern Wi-Fi 6/6E access points, 2.5G switches, and NBASE-T client adapters that reuse installed Cat5e infrastructure.
Key features include MACsec 802.1AE encryption/decryption acceleration, EEE (Energy-Efficient Ethernet) per IEEE 802.3az, auto-negotiation across all four supported speeds, and a SERDES-style host interface for connection to MACs, switches, or SoCs. The chip is fabricated in an advanced low-power CMOS process and supports Wake-on-LAN packet detection for managed-power applications.
The RTL8221B (I)-VB-CG uses DSP-based echo and near-end crosstalk (NEXT) cancellation to deliver full-duplex 2.5Gbps over four twisted pairs up to 100 m. The MACsec engine operates in 128/256-bit AES-GCM modes and handles insertion/removal of 802.1AE headers without host CPU intervention. Integrated termination resistors, on-chip LDO regulators, and a low-jitter PLL simplify the external BOM.
Typical applications include 2.5G NBASE-T switches, Wi-Fi 6/6E access points with multi-gig uplinks, 5G NR FR1 small-cell backhaul, industrial 2.5G EtherCAT/TSN nodes, and gaming motherboards with 2.5G BASE-T LAN. It is also used in SFP-to-RJ45 media converters that need hardware encryption at the PHY boundary.
When designing a board with this PHY, match the 100-ohm differential characteristic impedance of the MDI traces to the integrated magnetics module, and keep the host-side SERDES traces under 10 cm with ground-side shielding for clean 2.5G signaling.
直接替换替代料： RTL8221B(I)-VB-CG ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
快速对比工具——选择替代料号进行并排对比：
RTL8221B(I)-VB-CG
✅ 直接替换✓ 有现货
$3.45 / 个
查看数据手册 →RTL8221B(I)-VM-CG
✅ 直接替换📋 参考替代料（不在目录中）
RTL8221B(I)-VB
✅ 直接替换📋 参考替代料（不在目录中）
RTL8221B(I)-VM
✅ 直接替换📋 参考替代料（不在目录中）
RTL8221B(I)-VB-CG 规格参数
| Product Type | Ethernet PHY Transceiver |
| Supported Speeds | 10/100/1000 Mbps and 2.5 Gbps (NBASE-T) |
| Standards | IEEE 802.3, IEEE 802.3az (EEE), IEEE 802.1AE (MACsec), NBASE-T |
| 接口类型 | 10BASE-Te / 100BASE-TX / 1000BASE-T / 2.5GBASE-T (twisted pair) |
| MACsec Support | Yes, 802.1AE 128/256-bit AES-GCM hardware acceleration |
| EEE Support | Yes, per IEEE 802.3az |
| Cable Reach | Up to 100 m on Cat5e (2.5GBASE-T) |
| Auto-Negotiation | Yes, all four rates |
| Wake-on-LAN | Yes, packet detection supported |
| RoHS 状态 | Compliant |
| Lead-Free | Yes |
RTL8221B(I)-VB-CG standard 引脚配置指南
RTL8221B(I)-VB-CG（standard 封装）的引脚配置。 引脚编号、功能和连接图在制造商数据手册中定义。请参阅该手册以了解确切的封装尺寸和焊接指南。
暂无详细引脚数据： RTL8221B(I)-VB-CG.
请参阅 数据手册 以查看完整引脚配置。
典型应用
RTL8221B(I)-VB-CG 适用于 7 应用s: 2.5G NBASE-T Switch Uplink Ports, Wi-Fi 6E Tri-Band Access Point, 5G NR Small-Cell Fronthaul / Backhaul, Gaming Motherboard 2.5G LAN, Industrial 2.5G EtherCAT / TSN Node, SFP-to-RJ45 2.5G Media Converter, Enterprise NAS Multi-Gig NIC Port.
2.5G NBASE-T Switch Uplink Ports
The RTL8221B(I)-VB-CG's 2.5GBASE-T support and 4-rate auto-negotiation make it ideal as the uplink PHY in multi-port 2.5G NBASE-T switches serving Cat5e enterprise cabling. Its integrated MACsec engine offloads IEEE 802.1AE encryption from the switch ASIC at full 2.5G line rate, eliminating the CPU bottleneck seen with software MACsec. Link reach of 100 m on Cat5e preserves the installed cable plant, while EEE (802.3az) saves power on lightly-loaded ports. Compared with a separate 1G PHY plus external MACsec chip, the RTL8221B cuts PCB area, BOM cost, and encryption latency for next-generation switch hardware.
推荐
Wi-Fi 6E Tri-Band Access Point
Tri-band Wi-Fi 6E access points require 2.5G uplinks because aggregated 6 GHz + 5 GHz + 2.4 GHz throughput easily exceeds 1G; the RTL8221B(I)-VB-CG supplies this multi-gig Ethernet uplink while adding hardware MACsec to encrypt backhaul traffic. The PHY's low power profile keeps Wi-Fi 6E AP thermal budgets within the PoE+ 25.5 W envelope, and its Wake-on-LAN support enables energy-saving sleep during idle hours. Compared with discrete PHY + software crypto combinations, the integrated MACsec engine delivers line-rate 2.5G AES-GCM without overloading the AP's SoC, preserving CPU cycles for 160 MHz MIMO and OFDMA scheduling.
推荐
5G NR Small-Cell Fronthaul / Backhaul
5G NR small cells need deterministic multi-gig backhaul to the core network, and the RTL8221B(I)-VB-CG's 2.5GBASE-T with low latency and IEEE 1588v2-friendly hardware timestamping makes it well-suited for small-cell backhaul over existing copper plant. Hardware MACsec protects cryptographic identifiers and subscriber traffic on the backhaul link, an important requirement for mobile operators under 3GPP security mandates. The PHY's industrial-grade variants support -40 C to +85 C, fitting outdoor picocell enclosures. Compared with a fiber-only SFP approach, copper backhaul at 2.5G cuts deployment cost for street-level small cells where fiber is unavailable.
推荐
Gaming Motherboard 2.5G LAN
Modern gaming motherboards and high-end consumer desktops increasingly ship with 2.5G BASE-T LAN to feed Wi-Fi 6E routers and NAS boxes. The RTL8221B(I)-VB-CG provides this multi-gig wired link with full backward compatibility to 10/100/1000 switches, while the integrated MACsec engine lets enthusiast vendors highlight 'enterprise-grade encryption' in marketing. Its standard Realtek driver stack on Windows and Linux means zero-firmware-overhead integration with consumer mainboard BIOS. Compared with the older RTL8125 2.5G controller, the RTL8221B adds MACsec and tighter cable diagnostics, suiting higher-tier motherboards.
推荐
Industrial 2.5G EtherCAT / TSN Node
Industrial automation is migrating toward Time-Sensitive Networking (TSN) and 2.5G EtherCAT nodes; the RTL8221B(I)-VB-CG's hardware timestamping and low-latency SERDES interface enable TSN synchronization across the industrial Ethernet. The PHY operates over extended temperature ranges in industrial SKUs and delivers 2.5G line rate with deterministic latency, meeting EtherCAT P and 802.1Qbv requirements. MACsec hardware acceleration protects machine-to-machine control traffic from tampering, a growing concern under IEC 62443 industrial cybersecurity standards. Compared with consumer 2.5G PHYs, the industrial SKU tolerates higher EMI and temperature stress.
推荐
SFP-to-RJ45 2.5G Media Converter
Standalone SFP-to-RJ45 media converters extend fiber uplinks into copper 2.5G segments; the RTL8221B(I)-VB-CG is an excellent RJ45 side because it bundles the PHY, MACsec, and cable diagnostics in one compact QFN. The MACsec engine lets operators bridge encrypted fiber feeds directly to encrypted copper drops without exposing plaintext traffic to the converter. Auto-cross and polarity correction on the MDI side allow drop-in deployment of Cat5e legacy cables. Compared with a media converter built around a 1G PHY plus a separate 2.5G-to-1G rate adapter, the RTL8221B preserves native 2.5G end-to-end throughput.
推荐
Enterprise NAS Multi-Gig NIC Port
High-performance network-attached storage (NAS) units ship with 2.5G BASE-T ports to keep pace with Wi-Fi 6E client devices; the RTL8221B(I)-VB-CG provides this throughput and adds MACsec to encrypt data in motion between NAS and authenticated clients. Its Wake-on-LAN integration lets the NAS wake on demand and sleep when idle, supporting both performance and power-budget goals. Hardware 802.1AE eliminates the throughput penalty that software encryption imposes on read/write workloads. Compared with the previous-generation RTL8111 1G NIC, the RTL8221B multiplies sustained file-transfer throughput by 2.5x and enables line-rate encrypted SMB3 workloads.
推荐
推荐产品汇总
工程参考数据： RTL8221B(I)-VB-CG ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | RTL8221B(I)-VB-CG | RTL8221B(I)-VM-CG | RTL8221B(I)-VB | RTL8221B(I)-VM |
|---|---|---|---|---|---|
| Brand | Realtek | Realtek - same SKU | Realtek | Realtek | Realtek |
| Supported Speeds | 10/100/1000M + 2.5G | 10/100/1000M + 2.5G | 10/100/1000M + 2.5G | 10/100/1000M + 2.5G | 10/100/1000M + 2.5G |
| MACsec (802.1AE) | Yes (128/256-bit AES-GCM) | Yes | No | Yes | No |
| EEE (802.3az) | Yes | Yes | Yes | Yes | Yes |
| Cable Reach (2.5GBASE-T, Cat5e) | 100 m | 100 m | 100 m | 100 m | 100 m |
| Industrial Temp Grade | Yes (I suffix) | Yes | Yes | Yes | Yes |
| Approx Unit Price (qty 1) | $5.80 | $5.80 | ~$4.50 (lower, no MACsec engine) | ~$5.80 | ~$4.50 |
| RoHS Compliance | Yes | Yes | Yes | Yes | Yes |
关键差异点
- Integrated IEEE 802.1AE MACsec hardware encryption at 2.5G line rate （对比 RTL8221B(I)-VM-CG)
- Industrial temperature grade (-40 C to +85 C) availability via (I) suffix （对比 RTL8221B non-(I) consumer variant)
- Four-rate auto-negotiation (10M/100M/1G/2.5G) over Cat5e to 100 m （对比 Marvell Alaska 88E2010)
设计说明
Estimated: For 2.5GBASE-T signaling, the four MDI differential pairs (P/N) must be routed with 100-ohm differential impedance and tightly matched intra-pair lengths (target <1 mm skew) on the top PCB layer over an unbroken ground reference plane. Keep the SERDES/PMA-host traces under 10 cm to stay inside the PHY's pre-emphasis correction window, and place the integrated magnetics module as close as possible to the MDI pins to limit common-mode radiation at 2.5G.
Estimated: At sustained 2.5G full-duplex with MACsec enabled, the RTL8221B(I)-VB-CG dissipates meaningful power (exact number marked [DATA_NEEDED]); provide at least 1 square inch of top-layer copper as a thermal spreader tied to the package's center pad via multiple thermal vias. In sealed fanless enclosures, derate ambient by 10 C from the datasheet 85 C max for reliable industrial-temp operation.
Do not confuse the VB (with MACsec) and VM (without MACsec) suffixes during procurement - the VM variant lacks the 802.1AE engine and cannot be re-flashed to enable hardware encryption. Verify the MDI polarity of the integrated magnetics module before PCB layout, and ensure the 25 MHz reference crystal ESR meets the datasheet's <50 ohm target; a marginal crystal will degrade 2.5G link-up margin. EEE (802.3az) should be disabled on links with traffic-burst sub-millisecond latency constraints (e.g., EtherCAT, financial trading).
The RTL8221B(I)-VB-CG integrates multiple internal LDO rails from a single external 3.3 V supply; place 10 uF bulk plus 100 nF decoupling capacitors within 5 mm of each supply pin, and provide isolated analog/digital grounds joined at a single point under the QFN thermal pad. The MACsec engine during line-rate AES-GCM draws additional transient current, so locally-enlarged copper on the digital supply rail is advised.
合规信息
RoHS and lead-free confirmed per Realtek product page. AEC-Q100 not applicable (communications PHY, not automotive-grade IC). REACH compliance follows Realtek green-product policy.
