LM1973MX/NOPB National Semiconductor, LM1973MX/NOPB Datasheet

IC AUDIO ATTENUATR W/MUTE 20SOIC

LM1973MX/NOPB

Manufacturer Part Number
LM1973MX/NOPB
Description
IC AUDIO ATTENUATR W/MUTE 20SOIC
Manufacturer
National Semiconductor
Type
Audio Attenuatorr
Datasheet

Specifications of LM1973MX/NOPB

Applications
Consoles, MIDI
Mounting Type
Surface Mount
Package / Case
20-SOIC (7.5mm Width)
Pin Count
20
Screening Level
Commercial
Package Type
SOIC W
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Other names
*LM1973MX
*LM1973MX/NOPB
LM1973MX
© 2004 National Semiconductor Corporation
LM1973
µPot
General Description
The LM1973 is a digitally controlled 3-channel 76dB audio
attenuator fabricated on a CMOS process. Each channel
has attenuation steps of 0.5dB from 0dB–15.5dB, 1.0dB
steps from 16dB–47dB, and 2.0dB steps from 48dB– 76dB,
with a mute function attenuating 104dB. Its logarithmic at-
tenuation curve can be customized through software to fit
the desired application.
The performance of a µPot
excellent Signal-to-Noise Ratio, extremely low (THD+N),
and high channel separation. Each µPot contains a mute
function that disconnects the input signal from the output,
providing a minimum attenuation of 96dB. Transitions be-
tween any attenuation settings are pop free.
The LM1973’s 3-wire serial digital interface is TTL and
CMOS compatible; receiving data that selects a channel and
the desired attenuation level. The Data-Out pin of the
LM1973 allows multiple µPots to be daisy-chained together,
reducing the number of enable and data lines to be routed
for a given application.
Typical Application
µPot
and Overture
FIGURE 1. Typical Audio Attenuator
3-Channel 76dB Audio Attenuator with Mute
are trademarks of National Semiconductor Corporation.
Application Circuit
is demonstrated through its
DS011958
01195801
Key Specifications
n Total Harmonic Distortion + Noise:
n Frequency response:
n Attenuation range (excluding mute):
n Differential attenuation:
n Signal-to-noise ratio (ref. 4 Vrms):
n Channel separation:
Features
n 3-wire serial interface
n Daisy-chain capability
n 104dB mute attenuation
n Pop and click free attenuation changes
Applications
n Automated studio mixing consoles
n Music reproduction systems
n Sound reinforcement systems
n Electronic music (MIDI)
n Personal computer audio control
Connection Diagram
See NS Package Number M20B or N20A
Order Number LM1973M or LM1973N
Surface Mount Package
Dual-In-Line Plastic or
Top View
100 kHz (−3dB) (min)
December 1994
±
01195802
0.003% (max)
0.25dB (max)
www.national.com
110dB (min)
110dB (typ)
76dB (typ)

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LM1973MX/NOPB Summary of contents

Page 1

... Typical Application FIGURE 1. Typical Audio Attenuator Application Circuit µPot ™ and Overture ™ are trademarks of National Semiconductor Corporation. © 2004 National Semiconductor Corporation Key Specifications n Total Harmonic Distortion + Noise: n Frequency response: n Attenuation range (excluding mute): n Differential attenuation: n Signal-to-noise ratio (ref. 4 Vrms): ...

Page 2

... Absolute Maximum Ratings 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 V SS Power Dissipation (Note 3) ESD Susceptability (Note 4) Junction Temperature Electrical Characteristics The following specifications apply for all channels with V specified. Limits apply for T = 25˚ ...

Page 3

Electrical Characteristics Note 6: Limits are guaranteed to National’s AOQL (Average Output Quality Level). Note 7: At the present time the Crosstalk measurement is specified as a typical only, which is due to a hardware limitation of the automated test ...

Page 4

Typical Performance Characteristics Supply Current vs Supply Voltage Noise Floor Spectrum by FFT Amplitude vs Frequency THD vs V OUT 1 kHz by FFT V − 12V DD SS www.national.com 01195816 01195818 at 01195820 4 Supply Current vs ...

Page 5

Typical Performance Characteristics THD + N vs Frequency and Amplitude FFT of 20 kHz THD THD + N vs Amplitude ± kHz into CH1 @ (Continued) 01195822 01195824 6V 01195826 ...

Page 6

Application Information ATTENUATION STEP SCHEME The fundamental attenuation step scheme for the LM1973 µPot is shown in Figure 3. This attenuation step scheme, however, can be changed through programming techniques to fit different application requirements. One such example would be ...

Page 7

Application Information FIGURE 6. Mono Level Control with Panning Circuit INPUT IMPEDANCE The input impedance of a µPot is constant at a nominal 40 kΩ. To eliminate any unwanted DC components from propagating through the device it is common to ...

Page 8

Application Information TABLE 1. LM1973 Micropot Attenuator Register Set Description MSB: LSB Address Register (Byte 0) 0000 0000 0000 0001 0000 0010 Data Register (Byte 1) Contents Attenuation Level dB 0000 0000 0000 0001 0000 0010 0000 0011 : : ...

Page 9

Application Information DAISY-CHAIN CAPABILITY Since the µPot’s digital interface is essentially a shift register, multiple µPots can be programmed utilizing the same data and load/shift lines. As shown in Figure 11, for an n-µPot daisy-chain, there are 16n bits to ...

Page 10

Application Information FIGURE 10. Digitally-Controlled Logarithmic Gain Amplifier Circuit www.national.com (Continued) 01195813 FIGURE 11. n-µPot Daisy-Chained Circuit 10 01195812 ...

Page 11

Physical Dimensions inches (millimeters) unless otherwise noted Surface Mount Package Order Number LM1973M NS Package Number M20B Dual-In-Line Plastic Package Order Number LM1973N NS Package Number N20A 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. ...

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