| Number of channels (#) | 2 |
| Power supply (V) | 4.5 to 15 |
| Gain & attenuation (dB) | 0dB to -78dB with 0.5dB steps |
| THD + N @ 1 kHz (%) | 0.0008 |
| Interchannel crosstalk @ 1 kHz (dBFS) | -110 |
| Dynamic range (dB) | 115 |
| Operating temperature range (C) | 0 to 70 |
| Rating | Catalog |
- 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)
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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.