LM1973

Contents

The LM1973 is a digitally controlled 3-channel 76dB audio attenuator fabricated on a CMOS process. Each channel has attenuation steps of 0.5dB from 0dB-15.5dB, 1.0dB steps from 16dB-47dB, and 2.0dB steps from 48dB- 76dB, 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 LM1973'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 LM1973 allows multiple µPots to be daisy-chained together, reducing the number of enable and data lines to be routed for a given application.

• 3-wire serial interface
• Daisy-chain capability
• 104dB mute attenuation
• Pop and click free attenuation changes

• Automated studio mixing consoles
• Music reproduction systems
• Sound reinforcement systems
• Electronic music (MIDI)
• Personal computer audio control