GENERAL DESCRIPTION
The TEA6842H 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 single conversion receiver with integrated image
   rejection for IF = 10.7 MHz capable of selecting US FM,
   US weather, Europe FM, East Europe FM and Japan
   FM bands
• The tuning system includes FM mixer, AM mixer 1,
   AM mixer 2, crystal oscillator, VCO and PLL synthesizer
   on one chip.

FEATURES
• FM mixer for conversion of FM RF from 65 to 108 MHz
   to IF of 10.7 MHz; the mixer provides inherent image
   rejection
• FM RF mixer can be set to receive weather band radio
   up to 162.55 MHz
• Buffer output for weather band flag
• 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 reference for synthesizer PLL, IF count,
   timing for inaudible 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) or car radio integrated signal
   processor IC (TEF689x)
• Digital auto alignment circuit for conversion of
   LC oscillator tuning voltage to controlled alignment
   voltage of FM antenna tank circuit
• AGC PIN diode drive circuit for FM RF AGC; AGC
   detection at FM mixer input; the AGC PIN diode current
   can be set to a fixed value to allow local function for
   search tuning; AGC threshold is a programmable and
   keyed function switchable via the I2C-bus
• FM IF linear amplifiers with high dynamic input range (Continue ...)