company blog about Broadcom Introduces Industry's Highest Performance, Lowest Power BCM85821 Ethernet PHY

Mingjiada Electronics Broadcom introduces the industry's highest-performance and lowest-power BCM85821 800GbE PAM-4 PHY transceiver capable of driving a quad-channel 226-Gb/s PAM-4 at 113 Gbaud with support for both 400G DR1.2 and 1.6T DR4.2.

The BCM85821 leverages the market-leading 5nm PAM-4 PHY transceiver technology platform, validated with the BCM85812, to provide a pathway for accelerated availability of 1.6T OSFP-XD optical modules. Advanced Broadcom DSP technology and equalisation compensates for optical impairments while maintaining the world's lowest power pluggable optical modules and co-packaged optical solutions, enabling the deployment of 51.2-Tb/s and higher density switching ASICs.

The BCM85821 integrates a highly differentiated feature set, including market-leading FEC feature options and client switch ASIC SerDes interoperability, providing an unrivalled competitive advantage in the market.

In 800GbE mode, the BCM85821 converts eight 106 Gb/s channels on the client side to four 226 Gb/s channels to drive next-generation, high-density optical PAM-4 links within the OSFP-XD form factor.

Key Features

• Single-chip 4 × 200G PAM-4 PHY drives 800GbE over optics:

– Client side: 8 × 106G PAM-4

– Line side: 4 × 226G PAM-4 (128,120 inner code with 2-bit padding)

• Supports forward gearbox for backward compatibility with 400G optical modules:

– Client side: 8 × 53G PAM-4

– Line side: 4 × 106G PAM-4

• Supports client-side crossbar for flexible routing to various standards

• Supports 100G repeater mode

• Supports FEC monitoring in the repeater modes with a subsampling feature available for reduced power

• Supports FEC termination and generation

• Supports differential line-side output

• TX FIR support on both sides, line side (10 tap) and client side (7 tap)

• Client-side interface compliant with:

– IEEE 802.3ck C2C (Annex 135F) specification supporting medium-reach channels

– IEEE 802.3ck C2M (Annex 135G) specification supporting chip-to-module channels

– CEI-112G-VSR/MR specification supporting shortreach (VSR) and medium-reach (MR) channels

• IEEE 802.3cd standard-compliant KP4 and end-to-end FEC bypass operation:

– 800G/400G/200G/100G KP4 FEC

• Link-training support available on client side

• Line-side and client-side loopbacks

• Lowest-power 5-nm CMOS design

• Integrated AVS regulator

Applications

• Deployment of 1.6T OSFP-XD and 800G OSFP optical modules in hyperscale data centres

• 400G DR1.2

• 1.6T DR4.2

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