FEATURES

Radio Baseband Processors

Improves Sensitivity

Tuner Dynamic Range

− Quadrature Mixer, NCO, CIC Decimation

Filter, And FIR Filters

Coefficients

Generation

APPLICATIONS

DESCRIPTION

The AFEDRI8201 implements the receive channel analog

functions

required

for

intermediate-frequency

(IF)

sampled AM/FM and HD digital radio receivers. It is

designed to be used with TI’s DRIx50 digital baseband

processor. The AFEDRI8201 is programmed by the

DRIx50 for use in AM/FM and HD radio. The AFEDRI8201

oversamples the radio tuner IF output at speeds of up to

80MHz to reduce noise and improve dynamic range. The

radio tuner output IF is typically 10.7MHz for AM or FM as

well as 450kHz or 455kHz for AM, as desired. The

AFEDRI8201 then mixes, filters, and decimates the signal

to provide baseband I and Q output signals to the digital

baseband processor. The AFEDRI8201 also includes a

general-purpose 12-bit control digital-to-analog converter

(DAC) to provide a gain control signal or other analog

feedback to the tuner.

The DRIx50 digital baseband device writes control register

data as well as decimation filter coefficients to the

AFEDRI8201 through the industry-standard SPI control

interface. The baseband output signals are transported to

the DRIx50 through a general-purpose, high-speed serial

interface (TI’s Buffered Serial Ports, McBSP).

This unit uses 3.3V analog and 1.8V digital power

supplies. Typical power dissipation is 490mW. The digital

I/O lines can be powered by a 3.3V supply.

12−Bit

Pipeline

ADC

Auxiliary

DAC

Voltage

Reference

AUX

IFM

IFP

Quadrature

Mixer

NCO

CIC Filter

FIR Filter 1

FIR Filter 2A

DOUT0

DOUT1

DFSO

DCLK

DIN

DFSI

FIR Filter 2B

N

2

2

2

REFM VCM REFP

VGB

SPI Control

Interface

SCK

MOSI MISO

CS

Timing

Generator

PWD

SYNC RESET

Clock

Interface

MCLK

MCLKB

PRODUCTION DATA information is current as of publication date. Products

conform to specifications per the terms of Texas Instruments standard warranty.

Production processing does not necessarily include testing of all parameters.

AFEDRI8201

SBWS017F − SEPTEMBER 2003 − REVISED AUGUST 2005

IF ADC Front End for AM/FM and HD Radios

www.ti.com

Copyright

 2003−2005, Texas Instruments Incorporated

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.

SPI is a trademark of Motorola, Inc. All other trademarks are the property of their respective owners.