LM1972

www.ti.com

SNAS094D – APRIL 1995 – REVISED MARCH 2013

LM1972

μPot 2-Channel 78dB Audio Attenuator with Mute

Check for Samples: LM1972

1

FEATURES

DESCRIPTION

The LM1972 is a digitally controlled 2-channel 78dB

2

•

3-Wire Serial Interface

audio attenuator fabricated on a CMOS process.

•

Daisy-Chain Capability

Each channel has attenuation steps of 0.5dB from

•

104dB Mute Attenuation

0dB–47.5dB, 1.0dB steps from 48dB–78dB, with a

mute function attenuating 104dB. Its logarithmic

•

Pop and Click Free Attenuation Changes

attenuation

curve

can

be

customized

through

software to fit the desired application.

APPLICATIONS

The performance of a

μPot is demonstrated through

•

Automated Studio Mixing Consoles

its excellent Signal-to-Noise Ratio, extremely low

•

Music Reproduction Systems

(THD+N), and high channel separation. Each

μPot

•

Sound Reinforcement Systems

contains a mute function that disconnects the input

signal

from

the

output,

providing

a

minimum

•

Electronic Music (MIDI)

attenuation

of

96dB.

Transitions

between

any

•

Personal Computer Audio Control

attenuation settings are pop free.

The LM1972's 3-wire serial digital interface is TTL

KEY SPECIFICATIONS

and CMOS compatible; receiving data that selects a

•

Total Harmonic Distortion +

channel and the desired attenuation level. The Data-

Noise: 0.003 % (max)

Out pin of the LM1972 allows multiple

μPots to be

daisy-chained together, reducing the number of

•

Frequency response: 100 kHz (

−3dB) (min)

enable and data lines to be routed for a given

•

Attenuation range (excluding

application.

mute): 78 dB (typ)

•

Differential attenuation: ±0.25 dB (max)

•

Signal-to-noise ratio

(ref. 4 Vrms): 110 dB (min)

•

Channel separation: 100 dB (min)

Typical Application

Connection Diagram

Figure 1. Typical Audio Attenuator Application

Figure 2. 20-Lead SOIC - Top View

Circuit

See DW Package

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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

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PRODUCTION DATA information is current as of publication date.

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Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

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