Features Adaptive hysteresis Single supply operation Ground referenced input True zero crossing timing reference Operates from 2V to 12V supply voltage Handles inputs from 100 mVP-P to over 120VP-P with external resistor CMOS compatible logic Description The LM1815 is an adaptive sense amplifier and default gating circuit for motor control applications. The sense amplifier provides a one-shot pulse output whose leading edge coincides with the negative-going zero crossing of a ground referenced input signal such as from a variable reluctance magnetic pick-up coil. In normal operation, this timing reference signal is processed (delayed) externally and returned to the LM1815. A Logic input is then able to select either the timing reference or the processed signal for transmission to the output driver stage. The adaptive sense amplifier operates with a positive-going threshold which is derived by peak detecting the incoming signal and dividing this down. Thus the input hysteresis varies with input signal amplitude. This enables the circuit to sense in situations where the high speed noise is greater than the low speed signal amplitude. Minimum input signal is 150mVP-P. Applications Position sensing with notched wheels Zero crossing switch Motor speed control Tachometer Engine testing

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

Datasheets

Title		Size	Date	Other Language
	LM1815 Adaptive Variable Reluctance Sensor Amplifier	768 Kbytes	3-Mar-05

Part Number(s) (NSID)	Top View	Availability	Current Reported Stock	Budgetary Pricing	Pack Size
LM1815M/NOPB LM1815M RoHS Status	SOIC NARROW	Full production Lead Time: 6 weeks	Distributor Region Qty ARROW Worldwide 81 AVNET-EM Worldwide 273 DIGIKEY Worldwide 0 FARNELL Europe and Asia 180 FUTURE Worldwide 1770 NEWARK Americas 1433	$1.50 each at 1K+ pcs	rail of 55
LM1815MX/NOPB LM1815MX RoHS Status	SOIC NARROW	Full production Lead Time: 6 weeks	Distributor Region Qty ARROW Worldwide 4995 DIGIKEY Worldwide 0	$1.50 each at 1K+ pcs	reel of 2500
LM1815N/NOPB LM1815N RoHS Status	MDIP	Full production Lead Time: 6 weeks	Distributor Region Qty ARROW Worldwide 249 AVNET-EM Worldwide 225 DIGIKEY Worldwide 975 FUTURE Worldwide 321	$1.70 each at 1K+ pcs	rail of 25

Obsolete Versions

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LM1815MXEP	NONE	NATIONAL SEMICONDUCTOR	16 Nov 2008

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

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/quality/green.

National's certificate of product compliance 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
LM1815M/NOPB LM1815M	129.551 130.001	SOIC NARROW	14	1 1	260 235	Detail	N/A	N/A	NSUZXYTTE# LM1815M
LM1815MX/NOPB LM1815MX	129.551 130.001	SOIC NARROW	14	1 1	260 235	Detail	N/A	N/A	NSUZXYTTE# LM1815M
LM1815N/NOPB LM1815N	986.751 990.002	MDIP	14	1 1	NA NA	Detail	N/A	N/A	NSUZXYYTTE# LM1815N

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

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/quality/green.

National's certificate of product compliance 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)
LM1815M	SLM	0	44046	0	0	3532500	1	1002356520
LM1815MX	SLM	0	44046	0	0	3532500	1	1002356520
LM1815N	SLM	0	44046	0	0	3532500	1	1002356520

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/packaging/leadfree.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/quality/green.

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

Obsolete Versions

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LM1815MXEP	NONE	NATIONAL SEMICONDUCTOR	16 Nov 2008