NSC LMC1983CIV, LMC1983CIN Datasheet

August 1992

LMC1983
Digitally-Controlled Stereo Tone and Volume Circuit with
Three Selectable Stereo Inputs

General Description

The LMC1983 is a monolithic integrated circuit that provides
volume, balance, tone (bass and treble), loudness controls
and selection between three pairs of stereo inputs. These
functions are digitally controlled through a three-wire com­munication interface. Therearetwodigital inputs for easy in­terface to other audio peripherals such as stereo decoders.
The LMC1983 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
LMC1983’s SELECT OUT/SELECT IN external processor
loop.

Features

n Low noise and distortion

n Three pairs of stereo inputs
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

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

®

and Dolby®noise

Applications

n Stereo television
n Music reproduction systems
n Sound reinforcement systems
n Electronic music (MIDI)
n Personal computer audio control

LMC1983 Digitally-Controlled Stereo Tone and Volume Circuit with Three Selectable Stereo

Inputs

Block Diagram

DS011279-1

DNR®is a registered trademark of National Semiconductor Corporation.

®

Dolby

is a registered trademark of Dolby Labs.

© 1999 National Semiconductor Corporation DS011279 www.national.com

Absolute Maximum Ratings (Notes 1,

2)

If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.

+

Supply Voltage (V
Voltage at any Pin GND − 0.2V to V
Input Current at any Pin

(Note 3) 5 mA
Package Input Current (Note 3) 20 mA
Power Dissipation (Note 4) 500 mW
Junction Temperature +125˚C
Storage Temperature −65˚C to +150˚C

− GND) 15V

+

+ 0.2V

Lead Temperature

N Package,
(Soldering, 10 Seconds) +260˚C

V Package,
(Vapor Phase, 60 Seconds) 215˚C

Infrared, (15 Seconds) 220˚C

ESD Susceptability (Note 5) 2 kV

Operating Ratings (Notes 1, 2)

Temperature Range T

LMC1983CIN, LMC1983CIV −40˚C ≤ TA≤ +85˚C

Supply Voltage Range (V

+−V−

) 6Vto12V

MIN

≤ TA≤ T

MAX

Electrical Characteristics

The following specifications apply for V
0 dB, treble=0 dB, and loudness is off unless otherwise specified. All limits apply for T

+

=

=

9V, f

1 kHz, input signal (300 mV) applied to INPUT 1, volume=0 dB, bass

IN

=

=

T

+25˚C.

A

J

Symbol Parameter Conditions Typical Limit Unit

(Note 6) (Note 7) (Limit)
I
V

Supply Current 15 25 mA (max)

S

Input Voltage Clipping Level (1.0%THD), 2.3 2.0 V

IN

rms

Select Out (Pins 7, 22)

THD Total Harmonic Distortion Left and Right channels;

Output Pins 13, 16

=

V

0.3 V

IN

V

IN

V

IN

V

IN

rms

=

f

100 Hz, 1 kHz, 10 kHz

IN

=

2.0 V

rms

=

f

100 Hz, 1 kHz

IN

=

2.0 V

rms

=

f

10 kHz

IN

=

0.5 V

rms

; 0.008 0.1

; 0.4 1.0

; 0.5 1.0

; Bass and Treble 0.07 0.5

%

%

%

%

(max)

(max)

(max)

(max)

Tone Controls Set at Maximum

=

V

IN

Attenuator at −20 dB, Bass and Treble 0.06 0.15

0.3 V

; Volume

rms

%

(max)

Tone Controls Set at Maximum

DC Shifts V

=

IN

; between Any 2.0 4.0 mV (max)

0.3 V

rms

Two Adjacent Control Settings

=

V

IN

; 18 20 mV (max)

0.3 V

rms

All Mode and Input Positions

R

AC Output Impedance Pins 7, 22, (470Ω to Ground at Input) 150 200 Ω (max)

OUT

Pins 13, 16 26 40 Ω (max)

R

AC Input Impedance Pins 4, 5, 23, 24, 25 50 72 kΩ (max)

IN

35 kΩ (min)

Volume Attenuator Range Pins 13, 16; Volume 0.5 1.5 dB (max)

Attenuation at
0100010XXX000000 (0 dB)

0100010XXX101XXX (80 dB); 80 78 dB (min)
(Relative to Attenuation at 82 dB (max)
the 0 dB Setting)

Volume Step Size All Volume Attenuation Settings from

0100010XXX101XXX (80 dB) to 2.0 1.5 dB (min)
0100010XXX000000 (0 dB) (Note 9) 2.5 dB (min)

=

(min)

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Electrical Characteristics (Continued)

+

=

The following specifications apply for V
0 dB, treble=0 dB, and loudness is off unless otherwise specified. All limits apply for T

Symbol Parameter Conditions Typical Limit Unit

All Volume Attenuation Settings from
Channel-to-Channel 0100010XXX100110 (76 dB) to
Tracking Error 0100010XXX000000 (0 dB)

from

0100010XXX101XXX (80 dB) to

0100010XXX100111 (78 dB)
Mute Attenuation V
Bass Gain Range f

Bass Tracking Error f
Bass Step Size f

IN

IN

IN
IN

(Relative to Previous Level) 2.5 dB (max)

Treble Gain Range f

Treble Tracking Error f
Treble Step Size f

IN

IN
IN

(Relative to Previous Level) 2.5 dB (max)

Frequency Response V

IN

f

IN

(Relative to Signal Amplitude at 1 kHz)

Loudness Volume Attenuator=40 dB, Loudness

on (See
Gain at 100 Hz (Referenced 11.5 13.5 dB (max)

to Gain at 1 kHz) 9.5 dB (min)

Gain at 10 kHz (Referenced 6.5 8.5 dB (max)

to Gain at 1 kHz) 4.5 dB (min)
Signal-to-Noise Ratio V

IN

Measured at 1 kHz, R
Channel Balance All Volume Settings 0.2 1.0 dB (max)
Channel Separation Input Pins 4, 25: Output Pins 13, 16; 80 60 dB (min)

V

IN

Input-Input Isolation 470Ω to AC Ground on Unused Input 95 60 dB (min)

PSSR Power Supply Rejection

Ratio

f
V

Clock Frequency 5.0 1.0 MHz (max)

CLK

Logic “1” Input Voltage Pins 1, 27, 28 (IM Bus) 1.3 2.0 V (min)

IN(1)

+

V

Sinewave Applied to Pin 26

Pins 2, 3 2.9 5.5 V (min)

V

Logic “0” Input Voltage Pins 1, 27, 28 (IM Bus) 0.4 0.8 V (max)

IN(0)

Pins 2, 3 1.2 3.5 V (max)

V
V

Logic “1” Output Voltage Pin 28 (IM Bus) 2.0 V (min)

OUT(1)

Logic “0” Output Voltage Pin 28 (IM Bus) 0.4 0.8 V (max)

OUT(0)

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the deivce may occur. Operating Ratings indicate conditions for which the device is func­tional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed speci­fications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test conditions.

Note 2: All voltages are specified with respect to ground.
Note 3: When the input voltage (V

limited to 5 mA or less. The 20 mA package input current limits the number of pins that can exceed the power supply voltages with 5 mA current limit to four.
Note 4: The maximum power dissipation must be derated at elevated temperatures and is dictated by T

allowable power dissipation is P
+125˚C, and the typical junction-to-ambient thermal resistance, when board mounted, is 67˚C/W.

) at any pin exceeds the power supply voltages (V

IN

=

(T

D

)/θJAor the number given in the Absolute Maximum Ratings, whichever is lower. For the LMC1983CIN, T

JMAX−TA

=

9V, f

1 kHz, input signal (300 mV) applied to INPUT 1, volume=0 dB, bass

IN

=

=

T

+25˚C.

A

J

(Note 6) (Note 7) (Limit)

±

0.1

=

1.0 V

rms

=

100 Hz, Pins 13, 16

=

100 Hz, Pins 13, 16

=

100 Hz, Pins 13, 16 2.0 1.5 dB (min)

=

10 kHz, Pins 13, 16

=

10 kHz, Pins 13, 16

=

10 kHz, Pins 13, 16 2.0 1.5 dB (min)

105 86 dB (max)

±

±

0.1

±

±

0.1

±

1.5 dB (min)

±

2.0 dB (min)

±

12

12

10.0 dB (min)

±

14.0 dB (max)

±

1.5 dB (max)

±

10.0 dB (min)

±

14.0 dB (max)

±

1.5 dB (max)

Applied to Input 1 and Input 2;

=

20 Hz − 20 kHz

Figure 5

=

1.0 V

rms

=

1.0 V

rms

=

; 200 mV

9V

DC

)

, A Weighted, 95 90 dB (min)

=

470Ω

S

(Note 8)

, 100 Hz

rms

<

IN

V−or V

>

V+) the absolute value of the current at that pin should be

IN

, θJA, and the ambient temperature TA. The maximum

JMAX

±

0.1

±

1.0 dB (max)

32 28 dB (min)

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JMAX

=

=

Electrical Characteristics (Continued)

Note 5: Human body model; 100 pF discharged through a 1.5 kΩ resistor.
Note 6: Typicals are at T
Note 7: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).
Note 8: The Input-Input Isolation is tested by driving one input and measuring the output when the undriven input are selected.
Note 9: The Volume Step Size is defined as the change in attenuation between any two adjacent volume attenuation settings. The nominal Volume Step Size is 2 dB.

=

+25˚C and represent the most likely parametric norm.

J

Typical Performance Characteristics

Supply Current
vs Supply Voltage

THD vs
Load Impedance

THD vs V
(V

OUT

IN

Constant)

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Output Voltage
vs Supply Voltage

CCIR Output Noise
vs Volume Setting

THD vs Frequency

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DS011279-15

THD vs
Load Impedance

DS011279-13

Channel Separation
vs Frequency

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Mute Gain
vs Frequency

DS011279-17

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DS011279-18

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Typical Performance Characteristics (Continued)

Tone Control Response
with Equal Bass and
Treble Control Settings

DS011279-20

Connection Diagram

Loudness Response
vs Frequency

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Select Input Impedance
vs Frequency

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Order Number LMC1983CIN

Top View

See NS Package Number N28B

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DS011279-10

Top View

Order Number LMC1983CIV

See NS Package Number V28A

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