Product Brief
Applications
• ASIC-to-module interface
16×25 Gb/s front-panel application
• ASIC-to-module interface
8×56 Gb/s front-panel application
• High-density 10G, 25G, 40G, 50G,
100G, 200G, and 400G front-panel line-card applications
BCM81724
8x56-Gb/s PAM-4 to 16x25-Gb/s NRZ Reverse
Gearbox with 8x56-Gb/s PAM-4 Retimer Mode
Description
The Broadcom® BCM81724 is a single-chip 8×56-Gb/s to 16×25-Gb/s
NRZ reverse gearbox with 8×56-Gb/s PAM-4 Pass-Through mode PHY.
It supports both the PAM-4 and NRZ data formats. It supports Retimer,
Forward, and Reverse Gearbox modes. It also supports 1G, 10G, 25G, 40G,
50G, 100G, 200G, and 400G line-card applications.
On-chip clock synthesis is performed by a low-cost 156.25-MHz reference clock by high-frequency, low-jitter phase-locked loops (PLLs).
The BCM81724 is fabricated in advanced low-power, 16-nm CMOS technology.
The BCM81724 is available in a 19 mm × 19 mm, 0.8-mm pitch, 484-ball
BGA, RoHS-compliant package.
Features
• Host-side interface: 30 dB
• Line-side interface:
− 30 dB
− Chip-to-module (C2M) compliant
• Forward and Reverse Gearbox mode and Retimer mode
• Supports forward error correction (FEC)
• Supports 400G-CR8 mode
• Integrated AC-coupling capacitors at line-side receiver
• Multiple standard and line rate support for both PAM-4 and NRZ
• Continuous auto-adaptive equalizer
• Line- and system-side loopbacks
• PRBS generator and error checker
• Eye monitoring per lane on the line side, accessed through MDIO
• Single low-cost REFCLK input
• Recovered clock output
• Supports SGMII pass-through
• Interoperates with Broadcom ASIC and merchant switch silicon
• Low-power, 16-nm CMOS design
• 19 mm × 19 mm BGA, 0.8-mm ball pitch package
Single-Chip PHY
Product Brief
BCM81724 Block Diagram
ASIC
Host
Lane 1
25G NRZ/
56G PAM4
BCM81724
PLL
Auto-Negotiation/Link Training
Lane 8
25G NRZ/
56G PAM4
Control
Loop back
PRBS BERT
FEC Encoder/Decoder
Forward/Reverse Gearbox
CDR
REFCLK
Loop back
Lane 8
25G NRZ
Lane 9
25G NRZ/
56G PAM4
Lane 12
25G NRZ/
56G PAM4
Lane 13
25G NRZ
JTAG
Lane 16
25G NRZ
Power
Supplies
Line
Lane 1
25G NRZ/
56G PAM4
Lane 4
25G NRZ/
56G PAM4
Lane 5
25G NRZ
Module
MDIO 156.25 MHz 0.8V
1.8V
Ordering Information
Part Number
BCM81724A0KFSBG
Package
19 mm × 19 mm, 0.8-mm ball pitch, 484-ball BGA, RoHS-compliant
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For more information, please visit www.broadcom.com
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81724-PB100 03.01.18
