The LM1971 is a digitally controlled single channel audio attenuator fabricated on a CMOS
process. Attenuation is variable in 1 dB steps from 0 dB to −62 dB. A mute function disconnects the
input from the output, providing over 100 dB of attenuation.
The performance of the device is exhibited by its ability to change attenuation levels
without audible clicks or pops. In addition, the LM1971 features a low Total Harmonic Distortion
(THD) of 0.0008%, and a Dynamic Range of 115 dB, making it suitable for digital audio needs. The
LM1971 is available in both 8-pin plastic PDIP or SOIC packages.
The LM1971 is controlled by a TTL/CMOS compatible 3-wire serial digital interface. The
active low LOAD line enables the data input registers while the CLOCK line provides system timing.
Its DATA pin receives serial data on the rising edge of each CLOCK pulse, allowing the desired
attenuation setting to be selected.
- 3-Wire Serial Interface
- Mute Function
- Click and Pop Free Attenuation Changes
- 8-Pin Plastic PDIP and SOIC Packages Available
Key Specifications
- Total Harmonic Distortion 0.0008 % (Typ)
- Frequency Response > 200 kHz (−3 dB) (Typ)
- Attenuation Range (Excluding Mute) 62 dB (Typ)
- Dynamic Range 115 dB (Typ)
- Mute Attenuation 102 dB (Typ)
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| Number of channels | 1 |
| Power supply (V) | 4.5 to 15 |
| Gain & attenuation (dB) | 0dB to -62dB with 1.0dB steps |
| THD + N at 1 kHz (%) | 0.0008 |
| Dynamic range (dB) | 115 |
| Operating temperature range (°C) | -40 to 85 |
| Features | 1 Channel, Digitally controlled audio attenuator |