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LM1815

www.ti.com

SNOSBU8F –SEPTEMBER 2000–REVISED MARCH 2013

LM1815 Adaptive Variable Reluctance Sensor Amplifier

Check for Samples: LM1815

FEATURES

DESCRIPTION

The LM1815 is an adaptive sense amplifier and

• Adaptive Hysteresis

default gating circuit for motor control applications.

• Single Supply Operation

The sense amplifier provides a one-shot pulse output

• Ground Referenced Input

whose leading edge coincides with the negative-

going zero crossing of a ground referenced input

• True Zero Crossing Timing Reference

signal such as from a variable reluctance magnetic

• Operates from 2V to 12V Supply Voltage

pick-up coil.

• Handles Inputs from 100 mV

P-P

to over 120V

P-P

In normal operation, this timing reference signal is

with External Resistor

processed (delayed) externally and returned to the

• CMOS Compatible Logic

LM1815. A Logic input is then able to select either

the timing reference or the processed signal for

APPLICATIONS

transmission to the output driver stage.

• Position Sensing with Notched Wheels

The adaptive sense amplifier operates with a positive-

going threshold which is derived by peak detecting

• Zero Crossing Switch

the incoming signal and dividing this down. Thus the

• Motor Speed Control

input hysteresis varies with input signal amplitude.

• Tachometer

This enables the circuit to sense in situations where

• Engine Testing the high speed noise is greater than the low speed

signal amplitude. Minimum input signal is 150mV

P-P

Connection Diagram

Figure 1. Top View

14-Lead SOIC or PDIP

See D or NFF0014A Package

These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam

during storage or handling to prevent electrostatic damage to the MOS gates.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (17 pages)

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LM1815 www.ti.com SNOSBU8F – SEPTEMBER 2000 – REVISED MARCH 2013 LM1815 Adaptive Variable Reluctance Sensor Amplifier Check for Samples: LM1815 FEATURES 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 negativegoing zero crossing of a ground referenced input signal such as from a variable reluctance magnetic pick-up coil.
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LM1815 SNOSBU8F – SEPTEMBER 2000 – REVISED MARCH 2013 www.ti.com Absolute Maximum Ratings (1) (2) Supply Voltage 12V Power Dissipation (3) 1250 mW Operating Temperature Range −40°C ≤ TA ≤ +125°C Storage Temperature Range −65°C ≤ TJ ≤ +150°C Junction Temperature +150°C Input Current ±30 mA Lead Temperature (Soldering, 10 sec.) (1) (2) (3) 260°C “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be ensured.
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LM1815 www.ti.com SNOSBU8F – SEPTEMBER 2000 – REVISED MARCH 2013 Typical Performance Characteristics Mode 1 Minimum Arming Threshold vs Temperature Mode 2 Minimum Arming Threshold vs Temperature Figure 2. Figure 3. Mode 3 Minimum Arming Threshold vs Temperature Mode 1 Minimum Arming Threshold vs VCC Figure 4. Figure 5. Mode 2 Minimum Arming Threshold vs VCC Pin 3 VIN vs VSIGNAL Figure 6. Figure 7.
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LM1815 SNOSBU8F – SEPTEMBER 2000 – REVISED MARCH 2013 www.ti.com Typical Performance Characteristics (continued) 4 Pin 3 VIN vs VSIGNAL, RIN = 10kΩ Pin 3 VIN vs VSIGNAL, RIN = 20kΩ Figure 8. Figure 9. Pin 3 VIN vs VSIGNAL, RIN = 50kΩ Pin 3 Bias Current vs Temperature Figure 10. Figure 11. Peak Detector Charge Current vs Temperature Peak Detector Charge Current vs VCC Figure 12. Figure 13.
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LM1815 www.ti.com SNOSBU8F – SEPTEMBER 2000 – REVISED MARCH 2013 Typical Performance Characteristics (continued) Peak Detector Voltage vs Pin 3 VIN, Mode 1 Peak Detector Voltage vs Pin 3 VIN, Mode 2 Figure 14. Figure 15. Peak Detector Voltage vs Pin 3 VIN, Mode 3 Figure 16.
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LM1815 SNOSBU8F – SEPTEMBER 2000 – REVISED MARCH 2013 www.ti.com TRUTH TABLE Signal Input Pin 3 RC Timing Pin 14 Input Select Pin 11 Timing Input Pin 9 Gated Output Pin 10 ± Pulses RC L X Pulses = RC X X H H H X X H L L ± Pulses L L L Zero Crossing Figure 17.
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LM1815 www.ti.
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LM1815 SNOSBU8F – SEPTEMBER 2000 – REVISED MARCH 2013 www.ti.com APPLICATION HINTS Figure 18. LM1815 Oscillograms INPUT VOLTAGE CLAMP The signal input voltage at pin 3 is internally clamped. Current limit for the Input pin is provided by an external resistor which should be selected to allow a peak current of ±3 mA in normal operation.
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LM1815 www.ti.com SNOSBU8F – SEPTEMBER 2000 – REVISED MARCH 2013 MODE 1, PIN 5 OPEN The adaptive mode is selected by leaving device pin 5 open circuit. For input signals of less than ±135mV (i.e. 270 mVp-p) and greater than typically ±75mV (i.e. 150mVp-p), the input arming threshold is typically at 45mV. Under these conditions the input signal must first cross the 45mV threshold in the positive direction to arm the zero crossing detector, and then cross zero in the negative direction to trigger it.
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LM1815 SNOSBU8F – SEPTEMBER 2000 – REVISED MARCH 2013 www.ti.com REVISION HISTORY Changes from Revision E (March 2013) to Revision F • 10 Page Changed layout of National Data Sheet to TI format ............................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 1-Nov-2013 Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties.
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PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device LM1815MX/NOPB Package Package Pins Type Drawing SOIC D 14 SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 2500 330.0 16.4 Pack Materials-Page 1 6.5 B0 (mm) K0 (mm) P1 (mm) 9.35 2.3 8.0 W Pin1 (mm) Quadrant 16.
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PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM1815MX/NOPB SOIC D 14 2500 367.0 367.0 35.
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MECHANICAL DATA NFF0014A N0014A N14A (Rev G) www.ti.
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