LM1973

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SNAS093B – DECEMBER 1994 – REVISED MARCH 2013

APPLICATION INFORMATION

ATTENUATION STEP SCHEME

The fundamental attenuation step scheme for the LM1973

μPot is shown in Figure 16. This attenuation step

scheme, however, can be changed through programming techniques to fit different application requirements.

One such example would be a constant logarithmic attenuation scheme of 2dB steps for a panning function as

shown in Figure 18. The only restriction to the customization of attenuation schemes are the given attenuation

levels and their corresponding data bits shown in Table 1. The device will change attenuation levels only when a

channel address is recognized. When recognized, the attenuation level will be changed corresponding to the

data bits shown in Table 1. As shown in Figure 19, an LM1973 can be configured with a mono audio signal level

control and with a panning control which separates the mono signal into left and right channels. This circuit may

utilize the fundamental attenuation scheme of the LM1973 for the level control, but also possess a constant 2dB

panning control for the left and right channels as stated earlier.

LM1973 Channel Attenuation

vs Digital Step Value

Figure 16.

LM1973 Channel Attenuation

vs Digital Step Value

(Programmed 1.0dB Steps)

Figure 17. LM1973 1.0dB and 2.0dB

Attenuation Step Scheme

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