lmc835

Manufacturer Part Numberlmc835
DescriptionDigital Controlled Graphic Equalizer
ManufacturerNational Semiconductor Corporation
lmc835 datasheet
 


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LMC835 Digital Controlled Graphic Equalizer
General Description
The LMC835 is a monolithic digitally-controlled graphic
equalizer CMOS LSI for Hi-Fi audio The LMC835 consists
of a Logic section and a Signal Path section made of analog
switches and thin-film silicon-chromium resistor networks
The LMC835 is used with external resonator circuits to
make a stereo equalizer with seven bands
dB gain range and 25 steps each Only three digital inputs
are needed to control the equalization The LMC835 makes
it easy to build a mP-controlled equalizer
The signal path is designed for very low noise and distor-
tion resulting in very high performance compatible with
PCM audio
Connection Diagrams
Dual-In-Line Package
Top View
Order Number LMC835N
See NS Package N28B
C 1995 National Semiconductor Corporation
TL H 6753
Features
No volume controls required
Y
Three-wire interface
Y
14 bands 25 steps each
Y
g
12 dB or
g
6 dB gain ranges
Y
Low noise and distortion
Y
12 dB or
6
g
g
TTL CMOS logic compatible
Y
Applications
Hi-Fi equalizer
Y
Receiver
Y
Car stereo
Y
Musical instrument
Y
Tape equalization
Y
Mixer
Y
Volume controller
Y
Molded Chip Carrier Package
Order Number LMC835V
See NS Package V28A
TL H 6753 – 1
February 1995
TL H 6753 – 26
Top View
RRD-B30M75 Printed in U S A

lmc835 Summary of contents

  • Page 1

    ... The LMC835 is used with external resonator circuits to make a stereo equalizer with seven bands dB gain range and 25 steps each Only three digital inputs are needed to control the equalization The LMC835 makes it easy to build a mP-controlled equalizer The signal path is designed for very low noise and distor- ...

  • Page 2

    Block Diagram 2 ...

  • Page 3

    Absolute Maximum Ratings If Military Aerospace specified devices are required please contact the National Semiconductor Sales Office Distributors for availability and specifications b Supply Voltage Allowable Input Voltage (Note 1) b Storage Temperature T stg Lead ...

  • Page 4

    Electrical Characteristics SIGNAL PATH SECTION Symbol Parameter E Gain Error THD Total Harmonic A Distortion Maximum Output Voltage A O Max S N Signal to Noise Ratio A ...

  • Page 5

    Truth Tables DATA I (Band Selection ...

  • Page 6

    Test Circuits FIGURE 3 Test Circuit for AC Measurement FIGURE 4 Test Circuit for Leakage Current Measurement 6753 – 6753 – 6 ...

  • Page 7

    Test Circuits (Continued) Typical Performance Characteristics Supply Current vs Supply Voltage TL H 6753 – 7 FIGURE Converter FIGURE 6 Simple Word Generator Supply Current vs Temperature 6753 – 8 Input Capacitance vs ...

  • Page 8

    Typical Performance Characteristics Maximum Output Voltage vs Supply Voltage Distortion vs Frequency Range Distortion vs Output Voltage 6 dB Range g Gain vs Frequency 6 dB Range (Boost) g (Continued) Maximum Output Voltage Nominal Resistor vs Temperature ...

  • Page 9

    Typical Applications TABLE I Tuned Circuit Elements 12dB Z1 f (Hz) C ( 100k Z2 160 0 47m 0 ...

  • Page 10

    ... LMC835 Gain vs Frequency Range (All Boost or Cut) LMC835 Gain vs Frequency Range (All Boost or Cut) LMC835 Gain vs Frequency Range (1 kHz Boost or Cut) LMC835 Gain vs Frequency Range (1 kHz Boost or Cut) FIGURE 9 12-Band Equalizer 6753 – 6753 – 14 ...

  • Page 11

    ... FIGURE 10 Tuned Circuit for 680 12-Band Equalizer ( Figure 9 ) 510 LMC835 12 Band E Q Application Gain vs Frequency (1 kHz Boost or Cut) LMC835 12 Band E Q Application Gain vs Frequency (1 kHz Boost or Cut ...

  • Page 12

    Typical Applications (Continued) FIGURE 11 Single Supply Stereo Equalizer TL H 6753 – The output is used to bias the gyrators ...

  • Page 13

    ... Typical Applications (Continued) FIGURE 12 Stereo 7-Input 1-Output Mixers (THD is not as low as equalizer circuit) FIGURE 14 LMC835-COP404L CPU Interface TL H 6753 – 18 FIGURE 13 Stereo Volume Control Very Low THD 6753 – 6753 – 20 ...

  • Page 14

    ... MM74HC165 from 8 toggle switches The bits are shifted out to the DATA input of the LMC835 in sync with the clock When all data bits have been loaded CLOCK is inhibited and a STROBE pulse is generated this sequence is initiated by a START pulse ...

  • Page 15

    Application Hints (Continued) MODEL REDUCING EXTERNAL COMPONENTS The typical application shown in Figure 7 is switching noise free The DC-coupled circuit in Figure 16 is also switching noise free except switch turn ON OFF This ...

  • Page 16

    16 ...

  • Page 17

    ... Physical Dimensions inches (millimeters) Order Number LMC835N NS Package N28B 17 ...

  • Page 18

    ... Fax (81-41) 35-1 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 Order Number LMC835V NS Package V28A 2 A critical component is any component of a life ...