Dual Dolby* B-type noise reduction circuit
for playback applications
• Dual noise reduction (NR) channels
• Head pre-amplifiers
• Reverse head switching
• Automatic Music Search (AMS)
• Music scan
• Equalization with electronically switched time constants
• Dolby reference level = 387.5 mV
• 24 pins
• Improved EMC behaviour.
The TEA0675 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. Furthermore it includes electronically
switchable inputs for tape drivers with reverse heads.
This device also 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 externally by a resistor.
The device operates with power supplies in the range of
7.6 to 12 V, output overload level increasing with increase
in supply voltage.
Current drain varies with the following variables:
noise reduction 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 shrink dual in-line package; 24 leads (400 mil)
plastic small outline package; 24 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.
1996 Jun 07