The LM1972 is a digitally controlled 2-channel 78dB audio attenuator fabricated on a CMOS
process. Each channel has attenuation steps of 0.5dB from 0dB–47.5dB, 1.0dB steps from 48dB–78dB,
with a mute function attenuating 104dB. Its logarithmic attenuation curve can be customized through
software to fit the desired application.
The performance of a μPot is demonstrated through its 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
between any attenuation settings are pop free.
The LM1972'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 LM1972 allows
multiple μPots to be daisy-chained together, reducing the number of enable and data lines to be
routed for a given application.
