1FEATURES

234· Qualified for Automotive Applications

· Two Intermediate Frequency (IF)

Analog-to-Digital Converters (ADCs)

· Two 12-Bit Auxiliary Digital-to-Analog

Converters (DACs)

· 8-Bit Auxiliary ADCs with Four-Channel Input

Multiplexer (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

· 3.3-V/1.8-V Supply (Integrated Regulator

Available to Optionally Generate 1.8-V Supply)

· TQFP-144 (RFP) PowerPAD™ Package

APPLICATIONS

· IF-Sampled AM/FM Radio

· Hybrid Digital (HD) Digital Audio Broadcasting (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 75 MHz. 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 (20 mm × 20 mm) package and uses a 3.3-V and a 1.8-V power

supply. An onboard voltage regulator is included to optionally generate the 1.8-V digital supply for the AFE8221.