Features • 3-wire serial interface • Daisy-chain capability • 104dB mute attenuation • Pop and click free attenuation changes Description The LM1972 is a digitally controlled 2-channel 78dB audio attenuator fabricated on a CMOS process. Each channel has attenuation steps of 0.5dB from 0dB–47.5dB, 1.0dB steps from 48dB–78dB, 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 LM1972'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 LM1972 allows multiple μPots to be daisy-chained together, reducing the number of enable and data lines to be routed for a given application. Key Specification Total Harmonic Distortion + Noise: 0.003% (max) Frequency response: 100 kHz (−3dB) (min) Attenuation range (excluding mute): 78dB (typ) Differential attenuation: ±0.25dB (max) Signal-to-noise ratio (ref. 4 Vrms): 110dB (min) Channel separation: 100dB (min) Applications • Automated studio mixing consoles • Music reproduction systems • Sound reinforcement systems • Electronic music (MIDI) • Personal computer audio control

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Typical Application click for larger image	Connection Diagram click for larger image
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Datasheet

Title		Size	Date	Other Language
	LM1972 μPot 2-Channel 78dB Audio Attenuator with Mute	406 Kbytes	8-Mar-07	日本語

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Part Number(s) (NSID)	Top View	Availability	Current Reported Stock	Budgetary Pricing	Standard Pack Size
LM1972M/NOPB LM1972M RoHS	SOIC WIDE	Full production Lead Time: 16 weeks	Distributor Region Qty AVNET-EM Worldwide 79 DIGIKEY Worldwide 0 FUTURE Worldwide 72 KEIKONG Asia Pacific 2052 NEWARK Americas 8 TAYLOR Americas 155	$2.00 each at 1K+ pcs	rail of 36
LM1972MX/NOPB RoHS	SOIC WIDE	Full production Lead Time: 16 weeks	Distributor Region Qty DIGIKEY Worldwide 0 FUTURE Worldwide 1100	$2.00 each at 1K+ pcs	reel of 1000

Obsolete Versions

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LM1972N	NONE	NATIONAL SEMICONDUCTOR	05 Sep 2006

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM1972M	P2CMOS	0	49735	0	1	4330000	2	556689228
LM1972MX	P2CMOS	0	49735	0	1	4330000	2	556689228

Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

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Obsolete Versions

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LM1972N	NONE	NATIONAL SEMICONDUCTOR	05 Sep 2006