TEA6848H

GENERAL DESCRIPTION

The TEA6848H is a single IC with car radio tuner for AM, FM and Weather Band (WB) intended for microcontroller tuning with the I2C-bus. It provides the following functions:
• AM double conversion receiver for LW, MW and SW
(31 m, 41 m and 49 m bands) with IF1 = 10.7 MHz and
IF2 = 450 kHz
• FM double conversion receiver with integrated image
rejection for IF1 and for IF2 capable of selecting US FM,
US weather, Europe FM, East Europe FM and
Japan FM bands; fully integrated dynamic selectivity at
450 kHz FM IF2; FM demodulator with dynamic
threshold extension; centre frequency alignment of IF2
selectivity via the I2C-bus
• The tuning system includes VCO, crystal oscillator and
PLL synthesizer on one chip.

FEATURES

• FM mixer 1 for conversion of FM RF (65 to 108 MHz
and US weather band) to IF of 10.7 MHz; the mixer
provides inherent image rejection; for European and
US FM band/WB (weather band) the mixer is driven with
a ‘high’ injection Local Oscillator (LO); in Japan
FM band and East Europe FM band the mixer is driven
with a ‘low’ injection LO
• AM mixer 1 for conversion of AM RF to AM IF1 of
10.7 MHz
• LC tuner oscillator providing mixer frequencies for
FM mixer and AM mixer 1
• AM mixer 2 for conversion of AM IF1 to AM IF2 of
450 kHz
• Crystal oscillator providing mixer frequencies for
AM mixer 2 and FM mixer 2 and reference for
synthesizer PLL, IF count, timing for Radio Data System
(RDS) update and reference frequency for car audio
signal processor ICs
• Fast synthesizer PLL tuning system with local control for
inaudible RDS updating
• Timing function for RDS update algorithm and control
signal output for car audio signal processor ICs
(TEA688x, SAA77xx, TEF689x)
• Digital alignment circuit for bus controlled matching of
oscillator tuning voltage to FM antenna tank circuit
tuning voltage
• AGC PIN diode drive circuit for FM RF AGC; AGC
detection at FM mixer input; the AGC PIN diode drive
can be activated by the I2C-bus as a local function for
search tuning; AGC threshold is a programmable and
keyed function switchable via the I2C-bus
• FM IF linear amplifier with high dynamic input range (Continue ...)