National Semiconductor LMC1992 Technical data

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LMC1992 Digitally-Controlled Stereo Tone and Volume
Circuit with Four-Channel Input-Selector

December 1994

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 vol­ume, 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

b

2V) and has a maximum

gain of 0 dB.

The internal design is optimized for external capacitors hav­ing values of 0.1 mF or less. This allows the use of chip
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 sig­nal 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 7-band graphic equalizer connected to the
LMC1992’s select-out/select-in external processor loop.

Block and Connection Diagrams

Features

Y

Low noise and distortion

Y

Four stereo inputs

Y

40 volume levels including mute

Y

20 fader levels

Y

All attenuators havea2dBofattenuation per step

Y

Front/back fade control

Y

External processor loop

Y

Only three external components per channel

Y

Serial programmable: standard MICROWIRE

TM

interface

Y

Single supply operation: 6V to 12V supply voltage

Y

Protection address (similar to DS8906)

Y

DC-coupled inputs

Y

Single supply operation

Applications

Y

Automotive audio systems

Y

Sound reinforcement systems

Y

Home entertainmentÐstereo television and music re­production systems

Y

Electronic music (MIDI)

Order Number LMC1992CCN

TL/H/10789– 2

See NS Package Number N28B

Left channel shown. Pin numbers in parentheses are for the right channel.

DNRÉis a registered trademark of National Semiconductor Corporation.

TM

COPS

and MICROWIRETMare trademarks of National Semiconductor Corporation.

C

1995 National Semiconductor Corporation RRD-B30M75/Printed in U. S. A.

TL/H/10789

TL/H/10789– 1

Absolute Maximum Ratings (Notes 1 and 2)

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

a

Supply Voltage (V

Voltage at Any Pin GNDb0.2V to V

b

GND) 15V

a

a

0.2V

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

Electrical Characteristics The following specifications apply for V

channel 1, volume

e

0 dB, basse0 dB, treblee0 dB, and faderse0 dB unless otherwise specified. All limits T

§

25§C.

Symbol Parameter Conditions

I

S

V

V

Supply Current 27.0 mA (max)

Input Voltage Clipping Level (1.0% THD),

IN

Output Voltage Clipping Level (1.0% THD),

OUT

Select Out (Pins 8, 22)

Outputs (Pins 13, 14, 16, 17)

THD Total Harmonic Distortion All Four Channels

Volume Attenuator at 0 dB, Input Level 0.3 V
Volume Attenuator at

E

E

R

R

Output Noise All Four Channels CCIR/ARM Filter, R

nOUT

Output Noise All Four Channels CCIR/ARM Filter, R

nOUT

DC Output Impedance Pins 8, 22 100 150 X (max)

OUT

DC Input Impedance Pins 4, 5, 6, 7, 23, 24, 25, 26 2 MX

IN

Volume Attenuatoreb80 dB

Pins 13, 14, 16, 17 80 120 X (max)

Volume Attenuator Range Pins 16, 17; Volume Attenuation at

0101110100X (0 dB); (Absolute Gain)

01011000000 (80 dB); (Relative to Attenuation at

Volume Step Size All Volume Attenuation Settings from 01011001010 2.0 0.7 dB (min)

(60 dB) to 0101110100X (0 dB) (Note 9) 4.3 dB (max)

Channel-to-Channel Volume Fader Attenuation from 1XXX000000
Tracking Error (40 dB) to 1XXX1010X (0 dB)

Fader Attenuation Range Pins 16, 17; Fader Attenuation at

011XXX1010X (0 dB); (Absolute Gain)

011XXX00000 (40 dB); (Relative to Attenuation at

Fader Step Size All Fader Attenuation Settings from 011XXX00000 2.0 1.0 dB (min)

(40 dB) to 011XXX1010X (0 dB) (Note 10) 4.5 dB (max)

Storage Temperature

Lead Temperature

N Package, Soldering, 10 sec.

ESD Susceptibility (Note 5) 2000V

Pins 9, 10, 11, 19, 20, 21 850V

Operating Ratings (Notes 1 and 2)

Temperature Range T

C

LMC1992CCN 0§CsT

Supply Voltage Range (V

b

20 dB, Input Level 0.6 V

the 0 dB setting)

the 0 dB setting)

a

b

Vb) 6Vto12V

a

e

8V, f

e

1 kHz, input signal applied to

IN

Typical Limit Units

(Note 6) (Note 7) (Limit)

2.3 2.0 V

1.2 0.65 V

rms

e

0X 6.5 30.0 mV

S

e

0X

S

0.15 0.3 % (max)

0.03 0.1 % (max)

rms

5.0 20.0 mV

b

1.0

b

80.0 75.0 dB (min)

g

b

0.5

1.0

g

b

40 38.0 dB (min)

b

65§Ctoa150§C

a

260§C

s

s

T

MIN

T

A

MAX

s

70§C

A

e

T

A

J

(min)

rms

(min)

rms

(max)

rms

(max)

rms

1.5 dB (max)

1.0 dB (max)

1.5 dB (max)

e

2

a

Electrical Characteristics The following specifications apply for V

channel 1, volume

e

0 dB, basse0 dB, treblee0 dB, and faderse0 dB unless otherwise specified. All limits T

e

25§C. (Continued)

Symbol Parameter Conditions

Bass Gain Range f

Bass Tracking Error f

Bass Step Size f

Treble Gain Range f

Treble Tracking Error f

Treble Step Size f

Frequency Response

Channel Separation V

Input-Input Isolation V

PSRR Power Supply Rejection Ratio V

f

CLK

V

IN(1)

V

IN(0)

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device 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 de-rated at elevated temperatures and is dictated by T
allowable power dissipation is PD

e

Note 5: Human body model; 100 pF discharged through a 1.5 kX 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 front outputs when the undriven inputs 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.

Note 10: The Fader Step Size is defined as the change in attenuation between any two adjacent fader attenuation settings. The nominal Volume Step Size is 2 dB.

Clock Frequency 1.0 0.5 MHz (max)

Logic ‘‘1’’ Input Voltage 1.3 2.0 V (min)

Logic ‘‘0’’ Input Voltage 0.4 0.8 V (max)

) at any pin exceeds the power supply voltages (V

IN

e

b

(T

125§C, and the typical junction-to-ambient thermal resistance, when board mounted, is 67§C/W.

J

JMAX

e

25§C and represent the most likely parametric norm.

e

100 Hz, Pins 14, 16

IN

e

100 Hz, Pins 14, 16

IN

e

100 Hz, Pins 14, 16 2.0 1.0 dB (min)

IN

(Relative to Previous Level) 3.0 dB (max)

e

10 kHz, Pins 14, 16

IN

e

10 kHz, Pins 14, 16

IN

e

10 kHz, Pins 14, 16 2.0 1.0 dB (min)

IN

(Relative to Previous Level) 3.0 dB (max)

b

3 dB 450 kHz

b

0.3 dB (Relative to Signal Amplitude at 1 kHz) 20 kHz (min)

e

1.0 V

IN

IN

a

100 Hz Sinewave Applied to Pin 28

TA)/iJAor the number given in the Absolute Maximum Ratings, whichever is lower. For the LMC1992CCN, T

rms

e

1.0 V

rms

e

8VDC; 100 mV

(Note 8) 90 70 dB (min)

,

P-P

k

IN

Vbor V

l

Va) the absolute value of the current at that pin should be

IN

JMAX

e

8V, f

1 kHz, input signal applied to

IN

e

e

T

A

J

Typical Limit Units

(Note 6) (Note 7) (Limit)

g

g

g

g

12

0.1

12

0.1

g

10.0 dB (min)

g

1.0 dB (max)

g

10.0 dB (min)

g

1.0 dB (max)

97 70 dB (min)

40 31 dB (min)

, wJA, and the ambient temperature TA. The maximum

JMAX

3

Typical Performance Characteristics

Quiescent Current vs
Supply Voltage

TL/H/10789– 3 TL/H/10789– 4

Total Harmonic Distortion
vs Output AC Load

TL/H/10789– 6 TL/H/10789– 7

Channel Separation
vs Frequency

Maximum Output Swing vs
Supply Voltage

Total Harmonic Distortion
vs Select Out AC Load

Total Harmonic Distortion
vs Input Voltage

Output Noise Voltage
vs Frequency

TL/H/10789– 5

CCIR Output Noise Voltage
vs Volume Setting

TL/H/10789– 8

Attenuation vs Frequency

TL/H/10789– 9

4

TL/H/10789– 10

TL/H/10789– 11

Typical Performance Characteristics (Continued)

Tone Control Response
with Equal Bass and
Treble Control Settings

TL/H/10789– 12 TL/H/10789– 13 TL/H/10789– 14

Bass Tone Control
Response

Tone Control Response
with Reciprocal Bass and
Treble Control Settings

Treble Tone Control
Response

Select In Impedance
vs Frequency

Connection Diagram

TL/H/10789– 15

TL/H/10789– 16

TL/H/10789– 17

5