BCM54981
Brief
®
OCTAL-PORT 10/100/1000BASE-T GIGABIT ETHERNET TRANSCEIVER
SUMMARY OF BENEFITS
FEATURES
• Eight 10BASE-T/100BASE-TX/1000BASE-T Gigabit
Ethernet transceiver in a fully integrated 90 nm CMOS single
chip
• Energy efficient, low-cost, and low-power octal-port
integration enables single-row, high-port density switches
• Fully compliant with IEEE 802.3™, IEEE 802.3u, and
IEEE 802.3ab standards
• Provides compatibility with IEEE standard devices operating
at 10 Mbps, 100 Mbps, and 1000 Mbps at half-duplex and fullduplex
• Low power: 500 mW per port
• Low-cost solution for unmanaged switch applications
• SGMII and SerDes MAC interface options
• Lowers system bill of materials (BOM) cost and simplifies
system design
• Supports 10/100/1000BASE-T and 100BASE-FX on copper
interface
• Internal 100Ω Twisted Pair termination resistors
• Reverse MDI capability
• Eases system level debug
• Internal 100Ω Twisted Pair termination resistors eliminate
the need for external resistors. Saving eight resistors per port.
• Ability to reverse MDI, which results in ease of board design
and simplifies the layout in high-port density switch designs.
• Enhanced LED driver modes
• Line-side loopback
• Low electromagnetic interference (EMI) emissions
• Hardware-accelerated CableChecker™ diagnostics
• Robust cable-sourced electrostatic discharge (CESD)
tolerance
• Support for jumbo packets
• IEEE 1149.1 (JTAG) and 1149.6 (AC-JTAG) boundary scan
• Ethernet@Wirespeed™ and Super-Isolate mode support
• Remote PHY management capability allows PHY register
access through SGMII interface without the need of MDIO/
MDC.
• Enables use of low-cost magnetics, even in high-density (48+)
designs
• CableChecker characterizes cable plant condition and
immediately indicates cabling issues
- CableChecker detection of cable plant impairments
- Prevents erroneous equipment return due to bad cable
plants
- Prevents manufacturing fallout due to bad cable plants
• Operates with larger packets for wider range of packetprotocol support and improved efficiency
• Ease of manufacturing with JTAG support, simplified power
supply, and multiple MAC interfaces
BCM54981
10/100/1000BASE-T
Gigabit Ethernet
Transceiver
2x8 RJ-45s
BCM54981
with integrated magnetics
10/100/1000 Mbps
Ethernet Switch
BCM54981 System Diagram
OVERVIEW
BCM54981
TX DAC
TRD [3:0] {8}±
TRD [3:0] {7}±
TRD [3:0] {6}±
TRD [3:0] {5}±
XTALK
Canceller
Baseline
Wander
Correction
SGMII
Interface
SGIN {8:1}±
SGOUT {8:1}±
SCLK {8:1}±
TRD [3:0] {4}±
Echo
Canceller
TRD [3:0] {3}±
TRD [3:0] {2}±
DFE/
Trellis
Decoder
TRD [3:0] {1}±
FFE
PGA
ADC
Timing &
Phase
Recovery
LED
Interface
LED[4:1] {8:1}/
SLED[32:1]
SLED_CLK
SLED_STRB
SLED_IN
AutoNegotiation
MII
MGMT
Control
MII
Registers
RDAC [2:1]
MDIO [2:1]
MDC [2:1]
Modes
Bias
Generator
Clock
Generator
REFCLK2+
REFCLK1+
BCM54981 Reference Design
The BCM54981 consists of eight complete 10/100/1000BASE-T
interfaces allow fewer pins at the MAC/switch, which reduces the MAC/
Gigabit Ethernet transceivers integrated on a single monolithic CMOS
switch cost by enabling smaller die sizes that are possible with full GMII.
chip. The BCM54981 is optimized for low power and small footprint
This new device is the second member of Broadcom’s 90-nm Gigabit
size to enable high-port density applications. By lowering system cost
Ethernet copper PHY family, joining more than a dozen previousand reducing power dissipation by nearly 15% compared to previous
generation quad and single products. The 90-nm process is the optimal
generation PHY products, the BCM54981 enables a new class of costprocess that offers the best performance, lowest cost, and lowest power
effective Gigabit Ethernet equipment, driving the delivery of Gigabit
for highly integrated Gigabit Ethernet copper solutions. Devices based
Ethernet bandwidth to the desktop.
on the 90-nm process offer an excellent long-term cost curve, enabling
The BCM54981 DSP-based architecture and advanced power
management techniques combine with enhanced analog front-end design
to achieve robust and low-power operation over existing Category 5
twisted-pair wiring. The BCM54981 architecture not only meets the
requirements of IEEE 802.3, IEEE 802.3u, and IEEE 802.3ab but also
maintains the industry’s highest level of margin over IEEE requirements
for echo, near-end crosstalk (NEXT), and far-end crosstalk (FEXT). Low
power is the key to implementing high-density Gigabit Ethernet
switches, and at less than 500 mW per port the BCM54981 has the
smallest footprint and lowest power in the industry. In addition, the
BCM54981 has extremely low EMI emissions, which reduces the design
constraints required to meet EMI radiation specifications. The
BCM54981 provides the highest level of external component integration
in the smallest possible package resulting in PBC space saving of 40%
for high-density switch applications.
The BCM54981 supports the SGMII and SerDes MAC interfaces. The
SGMII and serial SerDes interfaces are reduced pin-count (6 and 4,
respectively, versus 25) versions of the GMII. These reduced pin-count
interfaces simplify design and lower system cost by reducing the number
of layers required to route high-density solutions. In addition, these
better cost reduction over time (compared to older technologies) without
having to redesign or requalify a new part.
Each BCM54981 port is fully independent and has individual interface,
control, and status registers and incorporates a number of advanced
features. A link-quality indicator LED gives installers an instant visual
indication if there are any problems with the wiring plant supporting
operation at the preferred speed. This includes physical wiring defects
that the BCM54981 cannot automatically correct and channel conditions
such as excessive cable length and return loss, crosstalk, echo, and noise.
Broadcom’s CableChecker software can be used with the device to
provide remote management of the cable and a first level of diagnostics
and fault isolation.
The BCM54981 has the industry's highest tolerance to electrostatic
discharge (ESD). This prevents ESD damage not only during
manufacturing but also during CESD events in the field. CESD is an
ESD event that occurs when an electrically charged network cable is
plugged into a network port. This is an issue that has become more
prevalent with contemporary cable installations, and the BCM54981
leads the industry in tolerance level.
Broadcom®, the pulse logo, Connecting everything®, the Connecting everything logo,
CableChecker™, and Ethernet@Wirespeed™ are among the trademarks of Broadcom Corporation and/
or its affiliates in the United States, certain other countries and/or the EU. Any other trademarks or trade
names mentioned are the property of their respective owners.
®
BROADCOM CORPORATION
5300 California Avenue,
Irvine, California 92617
© 2007 by BROADCOM CORPORATION. All rights reserved.
54981-PB00-R
05/01/07
Phone: 949-926-5000
Fax: 949-926-5203
E-mail: [email protected]
Web: www.broadcom.com