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TEA6849H

New In Car Entertainment car radio tuner IC with Precision Adjacent Channel Suppression (NICE-PACS)

Philips Electronics 

Philips Semiconductors

New In Car Entertainment car radio tuner IC with

Precision Adjacent Channel Suppression (NICE-PACS)

Product specification

TEA6849H

7 FUNCTIONAL DESCRIPTION

7.1 Oscillators

7.1.1 VCO

The varactor tuned VCO provides the local oscillator signal

for both FM and AM mixer 1. It has a frequency range of

162.9 to 248.2 MHz.

7.1.2 PLL

Fast synthesizer PLL tuning system with local control for

inaudible RDS updating.

7.1.3 CRYSTAL OSCILLATOR

The crystal oscillator provides a 20.5 MHz signal that is

used for:

• Reference frequency for frequency synthesizer PLL

• Local oscillator for AM mixer 2 and FM mixer 2

• Reference frequency for the IF counter

• Timing signal for the RDS update algorithm

• Reference frequency (75.368 kHz) for the TEA688x (car

audio signal processor - CASP) or TEF689x (car radio

integrated signal processor - CRISP).

7.2 DAA

To reduce the number of manual alignments in production

the following I2C-bus controlled Digital Auto Alignment

(DAA) functions are included:

• FM RF DAA

– 7-bit DAA circuitry for the conversion of the VCO

tuning voltage to a controlled alignment voltage for

the FM antenna tank circuit

• FM and AM level DAA

– Level DAA circuitry for alignment of slope (3-bit) and

starting point (5-bit) of the level curve

• IF2 centre DAA

– Centre frequency alignment (7-bit) of integrated

FM IF2 dynamic selectivity.

7.3 FM signal channel

7.3.1 FM MIXER 1

FM quadrature mixer converts FM RF (65 to 108 MHz and

weather band) to IF of 10.7 MHz. The FM mixer provides

inherent image rejection and high RF sensitivity.

It is capable of tuning the US FM, US weather,

Europe FM, Japan FM and East Europe FM bands:

• US FM = 87.9 to 107.9 MHz

• US weather FM = 162.4 to 162.55 MHz

• Europe FM = 87.5 to 108 MHz

• Japan FM = 76 to 91 MHz

• East Europe FM = 65 to 74 MHz.

7.3.2

BUFFER OUTPUT FOR WEATHER BAND FLAG

(PIN WBFLAG)

The buffer output on pin WBFLAG is HIGH for weather

band mode.

7.3.3 FM KEYED AGC

The AGC threshold is programmable and the keyed AGC

function is switchable via the I2C-bus. AGC detection

occurs at the input of the first FM mixer. If the keyed AGC

function is activated, the AGC is keyed only by the narrow

band level. The AGC PIN diode drive can be activated via

the I2C-bus as a local function for search tuning. The AGC

sources a constant 10 mA current into the FM PIN diode in

AM mode.

7.3.4 FM IF AMPLIFIER

The FM IF amplifier provides 18 dB amplification with high

linearity over a wide dynamic range.

7.3.5 FM MIXER 2

The FM mixer 2 converts 10.7 MHz FM IF1 to 450 kHz

FM IF2 in I and Q phase to achieve image rejection in the

demodulator.

2003 Dec 19

9

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