LM1971 Datasheet | National Semiconductor

Description The LM1971 is a digitally controlled single channel audio attenuator fabricated on a CMOS process. Attenuation is variable in 1 d B steps from 0 d B to - 62 d B. A mute function disconnects the input from the output, providing over 100 d B 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 d B, making it suitable for digital audio needs. The LM1971 is available in both 8-pin plastic DIP or SO packages. The LM1971 is controlled by a TTL/CMOS patible 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. Key Specifications n n n n n Total harmonic distortion 0.0008% > 200 k Hz (- 3 d B) Frequency response Attenuation range (excluding mute) 62 d B Dynamic range 115 d B Mute attenuation 102 d B (typ) (typ) (typ) (typ) (typ) Features n n n n 3-wire serial interface Mute function Click and pop free attenuation changes 8-pin plastic DIP and SO packages available Applications n n n n n n munication systems Cellular Phones and Pagers Personal puter audio control Electronic music (MIDI) Sound reinforcement systems Audio mixing automation Typical Application DS012353-1 FIGURE 1. Typical Audio Attenuator Application Circuit Overture™ is a trademark of National Semiconductor Corporation. © 1999 National Semiconductor Corporation DS012353 .national. Connection Diagram Dual-In-Line Plastic or Surface Mount Package DS012353-2 Top View Order Number LM1971M or LM1971N See NS Package Number M08A or N08E .national. Absolute Maximum Ratings (Notes 1, 2) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/...