LM1971N

Manufacturer Part NumberLM1971N
DescriptionDigitally Controlled 62 dB Audio Attenuator with/Mute
ManufacturerNational Semiconductor
LM1971N datasheet
 


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LM1971Overture
Digitally Controlled 62 dB Audio Attenuator with/Mute
General Description
The LM1971 is a digitally controlled single channel audio
attenuator fabricated on a CMOS process. Attenuation is
variable in 1 dB steps from 0 dB to −62 dB. A mute function
disconnects the input from the output, providing over 100 dB
of attenuation.
The performance of the device is exhibited by its ability to
change attenuation levels without audible clicks or pops. In
addition, the LM1971 features a low Total Harmonic Distor-
tion (THD) of 0.0008%, and a Dynamic Range of 115 dB,
making it suitable for digital audio needs. The LM1971 is
available in both 8-pin plastic DIP or SO packages.
The LM1971 is controlled by a TTL/CMOS compatible 3-wire
serial digital interface. The active low LOAD line enables the
data input registers while the CLOCK line provides system
timing. Its DATA pin receives serial data on the rising edge of
each CLOCK pulse, allowing the desired attenuation setting
to be selected.
Key Specifications
n Total harmonic distortion
>
n Frequency response
Typical Application
FIGURE 1. Typical Audio Attenuator Application Circuit
Overture
is a trademark of National Semiconductor Corporation.
© 2002 National Semiconductor Corporation
Audio Attenuator Series
n Attenuation range (excluding mute)
n Dynamic range
n Mute attenuation
Features
n 3-wire serial interface
n Mute function
n Click and pop free attenuation changes
n 8-pin plastic DIP and SO packages available
Applications
n Communication systems
n Cellular Phones and Pagers
n Personal computer audio control
n Electronic music (MIDI)
n Sound reinforcement systems
n Audio mixing automation
0.0008% (typ)
200 kHz (−3 dB) (typ)
DS012353
September 2002
62 dB (typ)
115 dB (typ)
102 dB (typ)
01235301
www.national.com

LM1971N Summary of contents