Product Description
Broadcom BCM85821, 5-nm CMOS 800G (8:4) PAM-4 Transceiver PHY
The Broadcom® BCM85821 is the industry’s highest-performance and lowest-power 800GbE PAM-4 PHY transceiver capable of driving four lanes of 226-Gb/s PAM-4 at 113 Gbaud, while supporting 400G DR1.2 and 1.6T DR4.2.
The BCM85821 leverages the market-leading 5-nm PAM-4 PHY transceiver technology platform, already proven with the BCM85812, and provides a path to accelerating 1.6T OSFP-XD optical module availability. The advanced Broadcom DSP technology and equalization techniques compensate for optical impairments while maintaining the world’s lowestpower pluggable optical modules and co-packaged optical solutions to enable the deployment of 51.2-Tb/s and higher-density switch ASICs.
The BCM85821 incorporates a highly differentiated feature set, including market-leading FEC capability options and client-side switch ASIC SerDes interoperability, to provide an unmatched competitive advantage to the market.
In 800GbE mode, the BCM85821 converts eight lanes of 106 Gb/s from the client side into four lanes of 226 Gb/s to drive next-generation high-density optical PAM-4 links inside OSFP-XD form-factor modules.
The BCM85821 also features crossbar on the client side for easier routing in the PCBs. The on-chip clock synthesis is performed by a low-cost 312.5- MHz or 625-MHz reference clock through high-frequency, lowjitter phaselocked loops.
5-nm CMOS 800G (8:4) PAM-4 Transceiver PHY
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
- 1.6T OSFP-XD and 800G OSFP optical module deployments inside hyperscale data center
- 400G DR1.2
- 1.6T DR4.2