LMC1992 NSC [National Semiconductor], LMC1992 Datasheet

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LMC1992

Manufacturer Part Number
LMC1992
Description
LMC1992 Digitally-Controlled Stereo Tone and Volume Circuit with Four-Channel Input-Selector
Manufacturer
NSC [National Semiconductor]
Datasheet

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Part Number:
LMC1992CCN
Quantity:
6 238
Part Number:
LMC1992N
Manufacturer:
NS/国半
Quantity:
20 000
C 1995 National Semiconductor Corporation
LMC1992 Digitally-Controlled Stereo Tone and Volume
Circuit with Four-Channel Input-Selector
General Description
The LMC1992 is a monolithic integrated circuit that provides
four stereo inputs bass and treble tone controls and vol-
ume balance and front-rear fader controls These functions
are digitally controlled through a three-wire communication
interface All of the LMC1992s functions are achieved with
only three external capacitors per channel It is designed for
line level input signals (300 mV
gain of 0 dB
The internal design is optimized for external capacitors hav-
ing values of 0 1
capacitors for coupling and tone control functions
Low noise and distortion result from using analog switches
and thin-film silicon-chromium resistor networks in the sig-
nal path
Volume and fader are at minimum and tone controls are flat
when supply voltage is first applied
Additional tone control can be achieved using the LMC835
stereo
LMC1992’s select-out select-in external processor loop
Block and Connection Diagrams
Left channel shown Pin numbers in parentheses are for the right channel
DNR is a registered trademark of National Semiconductor Corporation
COPS
TM
and MICROWIRE
7-band
TM
graphic
are trademarks of National Semiconductor Corporation
F or less This allows the use of chip
equalizer
TL H 10789
b
2V) and has a maximum
connected
to
the
Features
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Applications
Y
Y
Y
Y
Low noise and distortion
Four stereo inputs
40 volume levels including mute
20 fader levels
All attenuators have a 2 dB of attenuation per step
Front back fade control
External processor loop
Only three external components per channel
Serial programmable standard MICROWIRE
interface
Single supply operation 6V to 12V supply voltage
Protection address (similar to DS8906)
DC-coupled inputs
Single supply operation
Automotive audio systems
Sound reinforcement systems
Home entertainment stereo television and music re-
production systems
Electronic music (MIDI)
TL H 10789 – 1
See NS Package Number N28B
Order Number LMC1992CCN
RRD-B30M75 Printed in U S A
December 1994
TM
TL H 10789 – 2

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LMC1992 Summary of contents

Page 1

... LMC1992 Digitally-Controlled Stereo Tone and Volume Circuit with Four-Channel Input-Selector General Description The LMC1992 is a monolithic integrated circuit that provides four stereo inputs bass and treble tone controls and vol- ume balance and front-rear fader controls These functions are digitally controlled through a three-wire communication ...

Page 2

... N Package Soldering 10 sec 15V ESD Susceptibility (Note Pins Operating Ratings 20 mA Temperature Range 500 mW LMC1992CCN 125 C Supply Voltage Range (V The following specifications apply for and faders 0 dB unless otherwise specified All limits Conditions rms ...

Page 3

... DC P-P 100 Hz Sinewave Applied to Pin the absolute value of the current at that pin should JMAX or the number given in the Absolute Maximum Ratings whichever is lower For the LMC1992CCN T resistor kHz input signal applied Typical ...

Page 4

Typical Performance Characteristics Quiescent Current vs Supply Voltage TL H 10789–3 Total Harmonic Distortion vs Output AC Load TL H 10789–6 Channel Separation vs Frequency TL H 10789–9 Maximum Output Swing vs Supply Voltage TL H 10789 – 4 Total ...

Page 5

Typical Performance Characteristics Tone Control Response with Equal Bass and Treble Control Settings TL H 10789–12 Bass Tone Control Response Connection Diagram (Continued) Tone Control Response with Reciprocal Bass and Treble Control Settings TL H 10789 – 13 Select In ...

Page 6

... DATA and CLOCK inputs INPUT 1 –4 Four two-channel analog inputs are available (4 –7 23 –26) on the LMC1992 These pins should be dc-bi- ased to mid-supply SELECT OUT The selected INPUT signal is available at this (8 22) output This feature allows the use of external ...

Page 7

... The LMC1992’s SELECT OUT emitter followers allow addi- tional signal sources using emitter follower outputs (such as multiple LMC1992s ‘‘wired-ORed’’ together When this feature is in use the input channel of the LMC1992 not in use should be set to ‘‘open’’ input codes 01000XX0000 or 01000XX011X 10789– ...

Page 8

... TONE CONTROL RESPONSE Base and treble tone controls are included in the LMC1992 The tone controls use just two external capacitors for each stereo channel Each has a corner frequency determined by the value of C2 and C3 (Figure 4) and internal resistors in ...

Page 9

... Note 1 Negative transition on ENABLE clears previous address Clock must be low during transition Note 2 Additional don’t care states may be inserted here for ease of programming (Optional ) Note 3 Positive transition on ENABLE latches in new data if the LMC1992 has been addressed Clock can either be high or low during transition FIGURE 5 Clocking Data into the Standard MICROWIRE Interface ...

Page 10

... While these ‘‘don’t care’’ bits have no effect on their respective function the LMC1992 must receive them for proper operation If neglected erroneous ...

Page 11

... The following routines based on the flowchart shown in Fig- ure 6 are examples of COPS TM microcontroller instruction code that can be used to control the LMC1992 (see Nation- al Semiconductor’s COPS Microcontrollers Databook for more information) These routines arbitrarily select COPS register 0 for I O purposes When these routines are en- ...

Page 12

... Applications Information (Continued) FIGURE 6 General Data Transmission Flowchart to Send Serial Data to the LMC1992’s MICROWIRE Compatible Digital Inputs 10789 – 23 ...

Page 13

13 ...

Page 14

... National does not assume any responsibility for use of any circuitry described no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications Molded Dual-In-Line Package (N) Order Number LMC1992CCN NS Package Number N28B 2 A critical component is any component of a life ...

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