IC NOISE REDUCT SYS DYNAM 14SOIC

LM1894MX/NOPB

Manufacturer Part NumberLM1894MX/NOPB
DescriptionIC NOISE REDUCT SYS DYNAM 14SOIC
ManufacturerNational Semiconductor
TypeDynamic Noise Reduction
LM1894MX/NOPB datasheet
 


Specifications of LM1894MX/NOPB

ApplicationsAutomotive Systems, Players, TVMounting TypeSurface Mount
Package / Case14-SOIC (3.9mm Width), 14-SOLFor Use WithLM1894MTBD - BOARD EVALUATION LM1894
Lead Free Status / RoHS StatusLead free / RoHS CompliantOther names*LM1894MX
*LM1894MX/NOPB
LM1894MX
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LM1894
Dynamic Noise Reduction System DNR
General Description
The LM1894 is a stereo noise reduction circuit for use with
audio playback systems. The DNR system is non-
complementary, meaning it does not require encoded source
material. The system is compatible with virtually all prere-
corded tapes and FM broadcasts. Psychoacoustic masking,
and an adaptive bandwidth scheme allow the DNR to
achieve 10 dB of noise reduction. DNR can save circuit
board space and cost because of the few additional compo-
nents required.
Features
n Non-complementary noise reduction, “single ended”
n Low cost external components, no critical matching
Typical Application
*R1 + R2 = 1 kΩ total.
See Application Hints.
Order Number LM1894M, LM1894N, or LM1894MT
See NS Package Number M14A, N14A, or MTC14
FIGURE 1. Component Hook-Up for Stereo DNR System
DNR
®
is a registered trademark of National Semiconductor Corporation.
The DNR
®
system is licensed to National Semiconductor Corporation under U.S. patent 3,678,416 and 3,753,159.
Trademark and license agreement required for use of this product.
© 2004 National Semiconductor Corporation
n Compatible with all prerecorded tapes and FM
n 10 dB effective tape noise reduction CCIR/ARM
weighted
n Wide supply range, 4.5V to 18V
n 1 Vrms input overload
Applications
n Automotive radio/tape players
n Compact portable tape players
n Quality HI-FI tape systems
n VCR playback noise reduction
n Video disc playback noise reduction
DS007918
April 2002
®
00791801
www.national.com

LM1894MX/NOPB Summary of contents

  • Page 1

    ... National Semiconductor Corporation. The DNR ® system is licensed to National Semiconductor Corporation under U.S. patent 3,678,416 and 3,753,159. Trademark and license agreement required for use of this product. © 2004 National Semiconductor Corporation n Compatible with all prerecorded tapes and effective tape noise reduction CCIR/ARM weighted n Wide supply range, 4 ...

  • Page 2

    ... Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage Input Voltage Range Operating Temperature (Note 2) Storage Temperature Soldering Information Dual-In-Line Package Soldering (10 seconds) Electrical Characteristics 25˚ 300 kHz, circuit shown in Figure 1 unless otherwise specified ...

  • Page 3

    Electrical Characteristics 25˚ 300 kHz, circuit shown in Figure 1 unless otherwise specified Parameter Gain Amplifier Input Impedance Voltage Gain Peak Detector Input Impedance Voltage Gain Attack ...

  • Page 4

    Typical Performance Characteristics Supply Current vs Supply Voltage Power Supply Rejection Ratio (Referred to the Output) vs Frequency −3 dB Bandwidth vs Frequency and Control Signal www.national.com (Referred to the Output) 00791813 00791815 Gain of Control Path 10 kHz FM ...

  • Page 5

    Typical Performance Characteristics Main Signal Path Bandwidth vs Voltage Control Output Response (Continued) Peak Detector Response 00791803 00791805 5 00791804 www.national.com ...

  • Page 6

    External Component Guide (Figure 1) Component Value Purpose C1 0.1 µF– May be part of power supply, 100 µF or may be added to suppress power supply oscillation. C2, C13 1 µF Blocks DC, pin 2 and pin 13 are ...

  • Page 7

    Circuit Operation (Continued) PSYCHOACOUSTIC BASICS The dynamic noise reduction system is a low pass filter that has a variable bandwidth of 1 kHz to 30 kHz, dependent on music spectrum. The DNR system operates on three prin- ciples of psychoacoustics. ...

  • Page 8

    FIGURE 3. Output vs Frequency FIGURE 4. −3 dB Bandwidth vs Frequency and Control Signal www.national.com Application Hints The DNR system should always be placed before tone and volume controls as shown in Figure 1. This is because any adjustment ...

  • Page 9

    Application Hints (Continued) FIGURE 5. Bar Graph Display of Peak Detector Voltage FIGURE 6. Technique for Measuring S/N Improvement of the DNR System FOR FURTHER READING Tape Noise Levels 1. “A Wide Range Dynamic Noise Reduction System”, Black- mer, “dB” ...

  • Page 10

    Printed Circuit Layout www.national.com DNR Component Diagram 10 00791812 ...

  • Page 11

    Physical Dimensions inches (millimeters) unless otherwise noted SO Package (M) Order Number LM1894M NS Package Number M14A Molded Dual-In-Line Package (N) Order Number LM1894N NS Package Number N14A 11 www.national.com ...

  • Page 12

    ... BANNED SUBSTANCE COMPLIANCE National Semiconductor certifies that the products and packing materials meet the provisions of the Customer Products Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and contain no ‘‘Banned Substances’’ as defined in CSP-9-111S2. ...