Data Sheet
November 2011
AR9271 Single-Chip 1x1 MAC/BB/Radio/PA/LNA with USB
Interface for 802.11n 2.4 GHz WLANs
General Description
The Atheros AR9271 is a highly integrated single-
chip solution for 2.4 GHz 802.11n-ready wireless
local area networks (WLANs) that enables a high-
performance 1x1 configuration for wireless station
applications demanding robust link quality and
maximum throughput and range. The AR9271
integrates a multi-protocol MAC, baseband
processor, analog-to-digital and digital-to-analog
(ADC/DAC) converters, 1x1 radio transceiver, RF
switch, and USB interface in an all-CMOS device
for low power and small form factor applications.
The AR9271 implements half-duplex OFDM,
CCK, and DSSS baseband processing, supporting
72.2 Mbps for 20 MHz and 150 Mbps for 40 MHz
channel and IEEE 802.11b/g data rates. Other
features include signal detection, automatic gain
control, frequency offset estimation, symbol
timing, and channel estimation. The AR9271 MAC
supports the 802.11 wireless MAC protocol,
802.11i security, receive and transmit filtering,
error recovery, and quality of service (QoS).
The AR9271 supports one transmit traffic stream
and one receive traffic stream using one
integrated Tx chain and one receive chain for high
throughput and range performance. The Tx chain
combines baseband in-phase (I) and quadrature
(Q) signals, converts them to the desired
frequency, and drives the RF signal to the
antenna. The frequency synthesizer supports
frequencies defined by IEEE 802.11b/g/n
specifications.
The AR9271 supports frame data transfer to and
from the host using a USB interface that provides
interrupt generation/reporting, power save, and
status reporting. Other external interfaces include
serial EEPROM and GPIOs. The AR9271 is
interoperable with standard legacy 802.11b/g
devices.
Features
■ All-CMOS solution interoperable with IEEE
802.11b/g/n WLANs
■ Intergrated RF front end with high-output PA,
LNA, Rx/Tx switch
■ Internal diversity switch which selects antenna
1 or 2 for baseband signal processing
■ Supports optional external LNA, PA
■ 2.4 GHz WLAN MAC/BB processing
■ BPSK, QPSK, 16 QAM, 64 QAM, DBPSK,
DQPSK, and CCK modulation schemes
■ Supports 72.2 Mbps for 20 MHz and 150 Mbps
for 40 MHz channel operations
■ Wireless multimedia enhancements quality of
service support (QoS)
■ 802.11e-compatible bursting
■ Support for IEEE 802.11e and IEEE 802.11i
standards
■ WEP, TKIP, and AES hardware encryption
■ Reduced (short) guard interval
■ Frame aggregation
■ Block ACK
■ USB 2.0 interface
■ Supports the access of a serial peripheral (SPI)
compatible Flash memory, which includes
booting from an SPI Flash and auto-
installation
■ IEEE 1149.1 standard test access port and
boundary scan architecture supported
■ 68-pin, 8 mm x 8 mm LPCC package
AR9271 System Block Diagram
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