playback applications. TEA0679 Datasheet
I2C-bus controlled dual Dolby*
B-type noise reduction circuit for
Supersedes data of 1998 Jun 24
File under Integrated Circuits, IC01
1998 Nov 12
I2C-bus controlled dual Dolby* B-type noise
reduction circuit for playback applications
• Dual Noise Reduction (NR) channels
• Head preamplifiers
• Reverse head switching
• Automatic Music Search (AMS)
• Blank skip
• Mute position
• Equalization with electronically switched time constants
• Switch functions and level adjustment controlled via
• Optional switch inputs TTL compatible
• Dolby reference level = 387.5 mV
• Contained in a 32-pin small outline package
• Improved EMC behaviour.
The TEA0679T is a bipolar integrated circuit that provides
two channels of Dolby B noise reduction for playback
applications in car radios. It includes head and
equalization amplifiers with electronically switchable time
constants. The device also includes electronically
switchable inputs for tape drivers with reverse heads.
This device detects pauses of music in the Automatic
Music Search (AMS) scan mode (for applications with an
intelligent controlled tape driver) or AMS latch mode (for
applications with a simple controlled tape driver).
For both modes the delay time can be fixed by using an
external resistor. In the blank skip mode the IC can detect
pauses of music during playback and allows a
microcontroller to react on this situation.
The equalization amplifier gain adjustment, the output
offset adjustment and all switching functions are I2C-bus
controlled. Head switching and equalization time constant
switching can be controlled via separate pins (optional).
The device operates with power supplies from 7.6 to 12 V.
The output overload level increases with increases in
Current drain varies with the following variables:
• Supply voltage
• Noise reduction on/off
• AMS on/off.
Because of this current drain variation it is advisable to use
a regulated power supply or a supply with a long time
QUICK REFERENCE DATA
signal plus noise-to-noise ratio
plastic small outline package; 32 leads; body width 7.5 mm
Remark Dolby*: Available only to licensees of Dolby Laboratories Licensing Corporation, San Francisco, CA94111,
USA, from whom licensing and application information must be obtained. Dolby is a registered trade-mark of Dolby
Laboratories Licensing Corporation.
1998 Nov 12