Texas Instruments LM1973
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.FEATURES
1●2 3-Wire Serial Interface
● Daisy-Chain Capability
● 104dB Mute Attenuation
● Pop and Click Free Attenuation Changes
APPLICATIONS
● Automated Studio Mixing Consoles● Music Reproduction Systems
● Sound Reinforcement Systems
● Electronic Music (MIDI)
● Personal Computer Audio Control KEY SPECIFICATIONS
● Total Harmonic Distortion + Noise: 0.003 % (max)
● Frequency response: 100 kHz (−3dB) (min)
● Attenuation range (excluding mute): 76 dB (typ)
● Differential attenuation: ±0.25 dB (max)
● Signal-to-noise ratio (ref. 4 Vrms): 110 dB (min)
● Channel separation: 110 dB (typ)
DESCRIPTION
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.