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

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

Datasheets

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

Part Number(s) (NSID)	Top View	Availability	Current Reported Stock	Budgetary Pricing	Pack Size
LM1972M/NOPB LM1972M RoHS Status	SOIC WIDE	Full production Lead Time: 12 weeks	Distributor Region Qty ARROW Worldwide 260 DIGI-KEY Worldwide 2781 MOUSER Worldwide 176 NEWARK Americas 393 TAYLOR Americas 350	$2.00 each at 1K+ pcs	rail of 36
LM1972MX/NOPB LM1972MX RoHS Status	SOIC WIDE	Full production Lead Time: 12 weeks	Distributor Region Qty ARROW Worldwide 1000 AVNET-EM Worldwide 2000 DIGI-KEY Worldwide 0 MOUSER Worldwide 994 TAYLOR Americas 1000	$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

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LM1972.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LM1972 is located at RoHS Status.

Part Number(s) (NSID)	Weight (milligrams)	Type	Pins	MSL Rating	Peak Reflow	RoHS Status	CAD Symbols	Models	Package Marking Format
LM1972M/NOPB LM1972M	518.972 520.002	SOIC WIDE	20	3 2A	260 220	Detail	N/A	N/A	NSUZXYTTE# LM1972M
LM1972MX/NOPB LM1972MX	518.972 520.002	SOIC WIDE	20	3 2A	260 220	Detail	N/A	N/A	NSUZXYTTE# LM1972M

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LM1972.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LM1972 is located at RoHS Status.

CAD Symbols and Models N/A

Models N/A

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM1972M	P2CMOS	0	50860	0	1	4503500	2	578995367
LM1972MX	P2CMOS	0	50860	0	1	4503500	2	578995367

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.

For more information on Reliability Metrics, please click here.

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LM1972.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LM1972 is located at RoHS Status.

Obsolete Versions

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