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LM1973 Dataheets PDF



Part Number LM1973
Manufacturers National Semiconductor
Logo National Semiconductor
Description Pot3-Channel 76dB Audio Attenuator
Datasheet LM1973 DatasheetLM1973 Datasheet (PDF)

LM1973 µPot 3-Channel 76dB Audio Attenuator with Mute December 1994 LM1973 µPot™3-Channel 76dB Audio Attenuator with Mute General Description 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 applica.

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LM1973 µPot 3-Channel 76dB Audio Attenuator with Mute December 1994 LM1973 µPot™3-Channel 76dB Audio Attenuator with Mute General Description 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. Key Specifications n n n n n n Total Harmonic Distortion + Noise: 0.003% (max) Frequency response: 100 kHz (−3dB) (min) Attenuation range (excluding mute): 76dB (typ) ± 0.25dB (max) Differential attenuation: Signal-to-noise ratio (ref. 4 Vrms): 110dB (min) Channel separation: 110dB (typ) Features n n n n 3-wire serial interface Daisy-chain capability 104dB mute attenuation Pop and click free attenuation changes Applications n n n n n Automated studio mixing consoles Music reproduction systems Sound reinforcement systems Electronic music (MIDI) Personal computer audio control Typical Application Connection Diagram Dual-In-Line Plastic or Surface Mount Package DS011958-1 FIGURE 1. Typical Audio Attenuator Application Circuit DS011958-2 Top View Order Number LM1973M or LM1973N See NS Package Number M20B or N20A µPot™ and Overture™ are trademarks of National Semiconductor Corporation. © 1999 National Semiconductor Corporation DS011958 www.national.com Absolute Maximum Ratings (Notes 1, 2) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage (VDD–VSS) Voltage at Any Pin Power Dissipation (Note 3) ESD Susceptability (Note 4) Junction Temperature VSS 15V − 0.2V to VDD + 0.2V 150 mW 1800V 150˚C Soldering Information N Package (10 sec.) Storage Temperature +260˚C −65˚C to +150˚C Operating Ratings (Notes 1, 2) TMIN Temperature Range TMIN ≤TA ≤TMAX Supply Voltage (VDD − VSS) 0˚C TA ≤TA TMAX ≤ +70˚C 4.5V to 12V Electrical Characteristics (Notes 1, 2) The following specifications apply for all channels with VDD = +6V, VSS = −6V, VIN = 5.5 Vpk, and f = 1 kHz, unless otherwise specified. Limits apply for TA = 25˚C. Digital inputs are TTL and CMOS compatible. Symbol Parameter Conditions LM1973 Typical (Note 5) IS THD+N XTalk SNR Supply Current Total Harmonic Distortion plus Noise Crosstalk (Channel Separation) (Note 7) Signal-to-Noise Ratio Inputs are AC Grounded VIN = 0.5 Vpk @ 0dB Attenuation 0dB Attenuation for VIN VCH measured @ −76dB Inputs are AC Grounded @ −12dB Attenuation Limit (Note 6) 5 0.003 Units (Limits) 3 0.0008 110 mA (max) % (max) dB 120 104 110 96 dB (min) dB (min) dB (max) dB (max) dB (max) dB (min) dB (min) dB (min) dB (min) dB (min) dB (max) dB (max) nA (max) kΩ (min) kΩ (max) nA (max) MHz (max) V (min) V (max) V (max) V (min) A-Weighted AM Mute Attenuation Attenuation Step Size Error 0dB to −16dB −17dB to −48dB −49dB to −76dB Absolute Attenuation Error Attenuation @ 0dB Attenuation @ −20dB Attenuation @ −40dB Attenuation @ −60dB Attenuation @ −76dB Channel-to-Channel Attenuation Tracking Error ILEAK RIN IIN fCLK VIH VIL Analog Input Leakage Current AC Input Impedance Input Current Clock Frequency High-Level Input Voltage Low-Level Input Voltage Data-Out Levels (Pin 12) @ Pins 9, 10, 11 @ Pins 9, 10, 11 ± 0.05 ± 0.1 ± 0.25 0.01 19.8 39.5 59.3 74.5 0.5 19.0 38.5 58.0 73.0 Attenuation @ 0dB, −20dB, −40dB, −60dB Attenuation @ −76dB Inputs are AC Grounded Pins 2, 4, 18, VIN = 1.0 Vpk, f = 1 kHz @ Pins 9, 10, 11 @ 0V ± 0.5 ± 0.75 10.0 40 1.0 3 100 20 60 < VIN < 5V ± 100 2 2.0 0.8 0.1 5.9 VDD = 6V, VSS = 0V Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions which guarantee specific performance limits. This assumes that the device is within the Operating Ratings. Specifications are not guaranteed for parameters where no limit is given, however, the typical value is a good indication of device performance. Note 2: All voltages are measured with respect to GND (pins 1, 3, 5,.


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