BCM2051
PRODUCT
BCM2051
B C M 2 0 5 1
Brief
RADIO
O F
B E N E F I T S
802.11B
S U M M A R Y
F E AT U R E S
Zero IF,
conversion radio integrates
•
completesingle-chip direct IF.
802.11b RF and
Fully
external
•
count integrated VCO minimizescost. component
and reduces overall BOM
•
Single 2.7V to 3.3V voltage supply.
Operation over extended
•
robust radio performancetemperature range provides
in integrated laptop and
embedded designs.
Highly linear
•
free operation.receive path ensures robust, interference-
Exceptional
and out-of-band blocking
•
mitigates theadjacentofchannelwireless LAN, Bluetooth,
effects other
and microwave oven effects.
Monolithic implementation in a standard digital
•
CMOS process with minimal external components
provides a manufacturable low-cost 802.11b RF/IF
solution.
On-chip auto-calibration eliminates process variation
•
across components and mitigates temperature
variation, enabling it to be used in high-volume
applications.
Performance is
•
performance in optimized to ensure the robust
real-world operating environments.
Low power consumption
•
power wireless solutions. enables integration into low-
Minimum
•
solution forexternal BOM provides the lowest cost
802.11b radio solutions.
802.11b Application
Balun
BCM2051
802.11b
Radio
Diversity
Switch &
BPF
T/R
Switch
Power
Amp
BCM4301
802.11b
MAC & BB
System
Interface
Balun
Crystal
BROADCOM PROPRIETARY & CONFIDENTIAL
B C M 2 0 5 1
O V E R V I E W
BCM2051
802.11b Radio
Automatic
Calibration
Control
Control and
Data Interface
I/Q Output
RF Input
LO
Generation
PLL
Frac N
RF Output
I/Q Input
The
BCM2051
802.11b zero IF Radio is an integrated
transceiver device that has been optimized for use in 2.4-GHz
802.11b wireless systems. It has been designed to provide low-
power, low-cost, and robust communications for applications
operating in the globally available 2.4-GHz unlicensed ISM
band. It is fully compliant with the 802.11b specification and
meets or exceeds the requirements where appropriate to provide
the highest communication link quality of service.
The
BCM2051
features a simple, innovative shared LO
architecture that allows a high-performance radio implementation
in a single CMOS chip. A proprietary PLL design generates
quadrature LO signals in the 2.4-GHz band for both the transmitter
and receiver. The PLL is locked to a 12-MHz free running crystal
oscillator. A proprietary self-calibrating VCO is fully integrated
and does not require external VCO or tank circuits. This creates a
frequency agile LO, ensures the lowest phase noise performance
and covers the full 2.4-GHz ISM band.
The receiver front end consists a low noise amplifier, a single
side band mixer and on-chip low pass filter, which provide good
performance without a costly external IF band pass filter.
Because the entire receive channel is one chip, all sensitive
components are eliminated from the board design and this leads
to the most robust and noise-immune design, optimal for
integration in laptop computers and embedded applications.
An overall noise figure of 6 dB is achieved along with 85-dB gain
which can acheive -84-dBm sensitivity for 11-Mbps CCK
modulation.
The internal lowpass filter structure also features DC
cancellation loop and self-calibration circuitry, which
automatically adjusts circuit elements to compensate for any
process variation. This eliminates tuning and ensures that the
devices are uniform across process variation and temperature. An
RSSI signal is also generated in these amplifiers for the system
to determine signal strength. The output is a stable I/Q output for
direct interface to the BCM430X series of baseband/MAC
components.
The transmit signal is input through the I/Q input from the
baseband. It is then filtered and upconverted to RF using the
quadrature LO signals. The signal is then boosted to a minimum
1-mW output power level by an internal power amplifier. The
output signal is optimized to enable easy integration with widely
available power amplifiers and minimizes the linearity
requirements for these devices. Output power control is digitally
programmable from full power to low power in 4-dB steps.
The
BCM2051
is controlled directly from the baseband and MAC
through a fully digital control interface. This interface provides
control for the various sections of the chip, defines data transfers
and allows access to the various internal registers of the device.
The
BCM2051
is in a 64-pin LPCC package.
Broadcom
®
and the pulse logo
®
are trademarks of Broadcom Corporation
and/or its subsidiaries in the United States and certain other countries.
All other trademarks are the property of their respective owners.
For more information please contact us at:
Phone: 949-450-8700, FAX: 949-450-8710
Email: info@broadcom.com
Visit our web site at: www.broadcom.com
© 2001 by BROADCOM CORPORATION.
2051-PB00-R-11.7.01
BROADCOM CORPORATION
16215 Alton Parkway, P.O. Box 57013
All rights reserved.
Irvine, California 92619-7013
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