描述 Description

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.

特性 Features

? 3-Wire Serial Interface
? Daisy-Chain Capability
? 104dB Mute Attenuation
? Pop and Click Free Attenuation Changes
Key Specifications
? Total Harmonic Distortion + Noise: 0.003 % (max)
? Frequency response: 100 kHz (?3dB) (min)
? Attenuation range (excluding 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)