Overview
The LM1971MX/NOPB, produced by Texas Instruments, is a digitally controlled single-channel audio attenuator fabricated on a CMOS process. This device is designed to provide precise and smooth attenuation control, making it suitable for various audio applications. The LM1971 features a 3-wire serial interface for easy control by a microcontroller, allowing for attenuation adjustments in 1 dB steps from 0 dB to −62 dB. Additionally, it includes a mute function that provides over 100 dB of attenuation, ensuring click and pop-free transitions.
Key Specifications
| Parameter | Conditions | Typical | Limit |
|---|---|---|---|
| Supply Voltage (VDD) | 4.5V to 12V | - | - |
| Operating Temperature Range | -40°C to +85°C | - | - |
| Total Harmonic Distortion (THD) | VIN = 0.5Vpk @ 0 dB Attenuation | 0.0008% | 0.003% (max) |
| Dynamic Range | Referenced to Full Scale = +6 Vpk | 115 dB | - |
| Mute Attenuation | - | 102 dB | 96 dB (min) |
| Attenuation Step Size Error | 0 dB to −62 dB | 0.009 dB | 0.2 dB (max) |
| Input Impedance | - | 40 kΩ | - |
| Output Impedance | - | 25 kΩ to 35 kΩ | - |
| Package Type | - | 8-SOIC | - |
Key Features
- Digitally controlled single-channel audio attenuator with 3-wire serial interface (TTL/CMOS compatible).
- Attenuation variable in 1 dB steps from 0 dB to −62 dB.
- Mute function providing over 100 dB of attenuation.
- Click and pop-free attenuation changes.
- Low Total Harmonic Distortion (THD) of 0.0008%.
- Dynamic Range of 115 dB.
- Available in 8-pin plastic PDIP and SOIC packages.
- Constant input impedance of 40 kΩ and variable output impedance between 25 kΩ and 35 kΩ.
Applications
- Communication Systems
- Cellular Phones and Pagers
- Personal Computer Audio Control
- Electronic Music (MIDI)
- Sound Reinforcement Systems
- Audio Mixing Automation
Q & A
- What is the attenuation range of the LM1971?
The LM1971 provides attenuation in 1 dB steps from 0 dB to −62 dB.
- What is the mute function of the LM1971?
The mute function disconnects the input from the output, providing over 100 dB of attenuation.
- What is the Total Harmonic Distortion (THD) of the LM1971?
The THD of the LM1971 is 0.0008% at VIN = 0.5Vpk @ 0 dB Attenuation.
- What is the dynamic range of the LM1971?
The dynamic range of the LM1971 is 115 dB referenced to full scale = +6 Vpk.
- What are the package options for the LM1971?
The LM1971 is available in 8-pin plastic PDIP and SOIC packages.
- What is the input impedance of the LM1971?
The input impedance of the LM1971 is constant at 40 kΩ.
- How does the LM1971 handle attenuation step changes?
The LM1971 ensures click and pop-free attenuation changes, and it is recommended to send all data points for each attenuation level to maintain flawless operation.
- What is the operating temperature range of the LM1971?
The operating temperature range of the LM1971 is -40°C to +85°C.
- How is the LM1971 controlled?
The LM1971 is controlled by a 3-wire serial interface (TTL/CMOS compatible) using DATA, CLOCK, and LOAD lines.
- What are some common applications of the LM1971?
The LM1971 is used in communication systems, cellular phones and pagers, personal computer audio control, electronic music (MIDI), sound reinforcement systems, and audio mixing automation).
