LMC1982 Datasheet, PDF (1/14 Pages) National Semiconductor (TI) – Digitally-Controlled Stereo Tone and Volume Circuit with Two Selectable Stereo Inputs

December 1994
LMC1982
Digitally-Controlled Stereo Tone and Volume Circuit with
Two Selectable Stereo Inputs
General Description
The LMC1982 is a monolithic integrated circuit that provides
volume, balance, tone (bass and treble), enhanced stereo,
and loudness controls and selection between two pairs of
stereo inputs. These functions are digitally controlled
through a three-wire communication interface. There are two
digital inputs for easy interface to other audio peripherals
such as stereo decoders. The LMC1982 is designed for line
level input signals (300 mV–2V) and has a maximum gain of
−0.5 dB. Volume is set at minimum and tone controls are flat
when supply voltage is first applied.
Low noise and distortion result from using analog switches
and poly-silicon resistor networks in the signal path.
Additional tone control can be achieved using the LMC835
stereo 7-band graphic equalizer connected to the
LMC1982’s SELECT OUT/SELECT IN external processor
loop.
Features
n Low noise and distortion
n Two pairs of stereo inputs
n Enhanced stereo function
n Loudness compensation
n 40 position 2 dB/step volume attenuator plus mute
n Independent left and right volume controls
n Low noise-suitable for use with DNR^® and Dolby^® noise
reduction
n External processor loop
n Signal handling suitable for compact discs
n Pop-free switching
n Serially programmable: INTERMETAL bus (IM) interface
n 6V to 12V single supply operation
n 28 Pin DIP or PLCC package
Applications
n Stereo television
n Music reproduction systems
n Sound reinforcement systems
n Electronic music (MIDI)
n Personal computer audio control
Block and Connection Diagrams
DNR^® is a registered trademark of National Semiconductor Corporation.
Dolby^® is a registered trademark of Dolby Labs.
© 1999 National Semiconductor Corporation DS011028
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