bcm54981 Broadcom Corp., bcm54981 Datasheet - Page 2

• Manufacturer Part Number: bcm54981
• Description: Bcm54981 - Octal-port 10/100/1000base-t Gigabit Copper Transceiver With Remote Phy
• Manufacturer: Broadcom Corp.

The BCM54981 consists of eight complete 10/100/1000BASE-T
Gigabit Ethernet transceivers integrated on a single monolithic CMOS
chip. The BCM54981 is optimized for low power and small footprint
size to enable high-port density applications. By lowering system cost
and reducing power dissipation by nearly 15% compared to previous
generation PHY products, the BCM54981 enables a new class of cost-
effective Gigabit Ethernet equipment, driving the delivery of Gigabit
Ethernet bandwidth to the desktop.
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
Broadcom
CableChecker™, and Ethernet@Wirespeed™ are among the trademarks of Broadcom Corporation and/
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BROADCOM CORPORATION
5300 California Avenue,
Irvine, California 92617
© 2007 by BROADCOM CORPORATION. All rights reserved.
54981-PB00-R
®
, the pulse logo, Connecting everything
05/01/07
TRD [3:0] {8}±
TRD [3:0] {6}±
TRD [3:0] {5}±
TRD [3:0] {3}±
TRD [3:0] {2}±
TRD [3:0] {7}±
TRD [3:0] {4}±
TRD [3:0] {1}±
®
RDAC [2:1]
®
, the Connecting everything logo,
Correction
Negotiation
Baseline
Generator
Wander
PGA
Auto-
Bias
BCM54981 Reference Design
TX DAC
ADC
O V E R V I E W
Registers
Canceller
Recovery
Timing &
Phase
Echo
FFE
MII
interfaces allow fewer pins at the MAC/switch, which reduces the MAC/
switch cost by enabling smaller die sizes that are possible with full GMII.
This new device is the second member of Broadcom’s 90-nm Gigabit
Ethernet copper PHY family, joining more than a dozen previous-
generation quad and single products. The 90-nm process is the optimal
process that offers the best performance, lowest cost, and lowest power
for highly integrated Gigabit Ethernet copper solutions. Devices based
on the 90-nm process offer an excellent long-term cost curve, enabling
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.
Canceller
Decoder
Control
XTALK
MGMT
Trellis
DFE/
MII
Generator
Interface
Interface
SGMII
Clock
LED
SGIN {8:1}±
SGOUT {8:1}±
SCLK {8:1}±
LED[4:1] {8:1}/
SLED[32:1]
SLED_CLK
SLED_STRB
SLED_IN
MDIO [2:1]
MDC [2:1]
Modes
REFCLK2+
REFCLK1+
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