AFE8221 Datasheet, PDF (1/48 Pages) Texas Instruments – Dual IF Analog Front-End for Digital Radio

AFE8221
www.ti.com
SBAS394A – APRIL 2007 – REVISED MARCH 2008
Dual IF Analog Front-End for Digital Radio
FEATURES
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•2345 Two IF ADCs
• Two 12-Bit Auxiliary DACs
• 8-Bit Auxiliary ADCs with Four-Channel Input
MUX
• Integrated IF Digital Processing Core
• Integrated Circuitry for Third-Overtone Master
Clock Oscillator
• Wakeup Circuit/Real-Time Clock with Separate
Crystal Oscillator
• Flexible Data Interface Optimized for TMS
Family of Digital Baseband Processors
• Pin-Selectable SPI™ and I²C™ Control
Interfaces
• 3.3V/1.8V Supply (Integrated Regulator
Available to Optionally Generate 1.8V Supply)
• TQFP-144, PowerPAD™ Package
APPLICATIONS
• IF-Sampled AM/FM Radio
• HD, DAB Digital Radio
DESCRIPTION
The AFE8221 implements the intermediate frequency
(IF) sampling and processing functions of a digital
radio receiver system. It is designed to be used with
TI's digital radio baseband processors and AM/FM
tuners. The AFE8221 can also be programmed by
the baseband processor for use in conventional
AM/FM and digital radio. This unit includes two IF
inputs with associated filtering and digital processing
circuitry.
The receive circuit oversamples the radio tuner IF
output to reduce noise and improve dynamic range.
The IF analog-to-digital converter (ADC) oversamples
the IF input at rates up to 75MHz. The AFE8221 then
digitally mixes, filters, and decimates the signal to
provide I and Q output signals to the baseband
processor. A clock oscillator circuit is provided that
can be used with an appropriate third-overtone crystal
and external tank circuit to generate the sampling
clock for the IF ADCs.
The AFE8221 also includes a real-time clock and
associated low-power oscillator circuit. Two auxiliary
digital-to-analog converters (DACs) are included for
system control functions. An 8-bit auxiliary ADC and
input multiplexer (MUX) can be used for system
diagnostic functions. Other features include 12
general-purpose input/output (GPIO) lines,
programmable interrupt generators, and an I²C
master for communication between the AFE and the
tuner(s).
The AFE8221 is available in a TQFP-144 (20mm ×
20mm) package and uses a 3.3V and a 1.8V power
supply. An onboard voltage regulator is included to
optionally generate the 1.8V digital supply for the
AFE8221.
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Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PowerPAD is a trademark of Texas Instruments.
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SPI is a trademark of Motorola, Inc.
3
I2C is a trademark of NXP Semiconductors.
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All other trademarks are the property of their respective owners.
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PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2007–2008, Texas Instruments Incorporated