
FEATURES
12-BIT, 80MSPS ADC
INTEGRATED DIGITAL DOWNCONVERTER (DDC):
Quadrature Mixer/NCO
CIC Decimation Filter
FIR Filters
MIXER: 32-BIT FREQUENCY AND PHASE
DECIMATION RATIO: 32 to 4096
USER PROGRAMMABLE FIR FILTERS WITH
16-BIT COEFFICIENTS
12-BIT AUXILIARY DAC
DATA INTERFACE COMPATIBLE WITH TI C5x/C6x
DSP BUFFERED SERIAL PORT (McBSP):
Code Composer Module for Easy Software
Generation
SPI
CONTROL INTERFACE
3.3V ANALOG, 1.8V DIGITAL SUPPLY
1.8V to 3.3V I/O SUPPLY
TQFP-48
APPLICATIONS
SOFTWARE RADIOS
IF RECEIVE CHANNEL
DIGITAL RADIO RECEIVERS
NARROWBAND RECEIVERS
DESCRIPTION
The AFE8201 consists of a general-purpose, 80MSPS,
12-bit analog-to-digital converter (ADC), a digital
downconverter (DDC), and user-programmable digital
filters. It is designed to sample narrowband (2.5MHz or
less) IF signals and digitally mix, filter, and decimate the
signals to baseband.
The DDC consists of a digital quadrature mixer followed
by a CIC decimation filter and FIR filters. The mixer
frequency and initial phase are independently
programmed by 32-bit control words.
After the CIC filter, the internal I and Q signals are
passed on to the first FIR filter, which can implement
even, odd, halfband, and arbitrary impulse responses
with up to 62 taps using 16-bit coefficients.
Following the first FIR filter are two parallel FIR filters
that can be used to provide two output streams or
interleaved to form one extended filter with up to 262
taps.
The
AFE8201
also
general-purpose auxiliary digital-to-analog converter
(DAC) for applications such as AGC amplifier control.
Control register data as well as decimation filter
coefficients are written to the AFE8201 through the
industry-standard SPI control interface. The baseband
output signals are transported through a general-
purpose, high-speed serial interface that is compatible
with TI C5x/C6x DSP family buffered serial ports
(McBSP).
contains
a 12-bit
12Bit
Pipeline
ADC
Auxiliary
DAC
Voltage
Reference
AUX
IFM
IFP
Quadrature
Mixer
NCO
CIC Filter
FIR Filter 1
FIR Filter 2A
2
D
DOUT0
DOUT1
DFSO
DCLK
DIN
DFSI
FIR Filter 2B
N
2
2
REFM VCM
REFP
VGB
SPI Control
Interface
SCK
MOSI MISO CS_N
Timing
Generator
PWD
SYNC RST_N
Clock
Interface
MCLK
MCLKB
P
AFE8201
SBWS016A OCTOBER 2003 REVISED JANUARY 2005
IF Analog-to-Digital Converter
with Digital Downconverter
www.ti.com
Copyright
20032005, Texas Instruments Incorporated
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