TEF6894H

General description

The TEF6894H is a monolithic BiMOS integrated circuit comprising the stereo decoder function, weak signal processing and ignition noise blanking facility for AM and FM combined with input selector and tone/volume control for AM and FM car radio applications. The device operates with a supply voltage of 8 to 9 V.

Features

General

• High integration
• No external components except coupling capacitors for signal inputs and outputs
• QFP44 package with small Printed-Circuit Board (PCB) footprint.

I²C-bus

• Fast mode 400 kHz I²C-bus, interfaces to logic levels ranging from 2.5 to 5 V
• Gated I²C-bus loop through to tuner IC
• Eases PCB layout (crosstalk)
• Allows mix of 400 kHz and 100 kHz busses
• Low bus load reduces crosstalk
• Buffered I/O circuit
• Supply voltage shift between both buses allowed.
• Shortgate function offers easy control with automatic gating of a single transmission; suited for TEA684x
• Autogate function offers transparent microcontroller control with automatic on/off gating (programmable address).

Stereo decoder

• FM stereo decoder with high immunity to birdy noise and excellent pilot cancellation
• Integrated IF roll-off correction controlled via I²C-bus
• De-emphasis selectable between 75 and 50 ms via I²C-bus.

Noise blanking

• New fully integrated AM noise blanker with excellent performance
• Fully integrated FM noise blanker with superior performance.

Weak signal processing

• FM weak signal processing with detectors for RF level, Ultrasonic Noise (USN) and Wideband AM (WAM) information
• AM weak signal processing with detectors for level information
• AM processing with soft mute and High Cut Control (HCC)
• FM processing with soft mute, stereo blend and HCC
• Setting of the sensitivity of the detectors and start and slope of the control functions via I²C-bus
• Weather band de-emphasis
• Level, USN and WAM read-out via I²C-bus (signal quality detectors)
• Full support of tuner AF update functions with TEA684x tuner ICs, FM audio processing holds the detectors for the FM weak signal processing in their present state during RDS updating.

Tone/volume part

• Input selector for four inputs:
• Two external stereo inputs (CD and TAPE)
• One mono input (PHONE)
• One internal stereo input (AM or FM).
• Integrated tone control and audio filters without external components
• Volume control from +20 to -79 dB in 1 dB steps; programmable 20 dB loudness control included
• Programmable loudness control with bass boost or as bass and treble boost
• Treble control from -14 to +14 dB in 2 dB steps
• Bass control from -14 to +14 dB in 2 dB steps with selectable characteristics
• Good undistorted performance for any step size, including mute
• Audio Step Interpolation (ASI) available for the following audio controls:
• Mute
• Loudness
• Volume/balance
• Bass
• Fader.
• ASI also realizes Alternative Frequency (AF) mute for inaudible RDS update
• Integrated beep generator
• Navigation (NAV) input
• Output mixer circuit for beep or NAV signal at output stages.

Products/packages

All type numbers in the table below are discontinued. See the table Discontinued information for more information.

Quality/reliability/chemical content

All type numbers in the table below are discontinued. See the table Discontinued information for more information.

Quality and reliability disclaimer

Discontinued information

Block diagrams/pinning

Design support

Application Notes

AN02106; Car Radio Integrated Signal Processor TEF6890H, TEF6892H, TEF6894H (2002-12-09)

AN10106; Car Radio Integrated Signal Processor TEF6890H, TEF6892H, TEF6894H (2002-11-20)

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Disclaimers

• General product disclaimer
• Quality and reliability disclaimer