SNOS724F August   2000  – February 2024 LMC6492 , LMC6494

PRODUCTION DATA  

  1.   1
  2. 1Features
  3. 2Applications
  4. 3Description
  5. 4Pin Configuration and Functions
  6. 5Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Typical Characteristics
  7. 6Application and Implementation
    1. 6.1 Application Information
      1. 6.1.1 Input Common-Mode Voltage Range
      2. 6.1.2 Rail-to-Rail Output
      3. 6.1.3 Compensating for Input Capacitance
      4. 6.1.4 Capacitive Load Tolerance
    2. 6.2 Typical Application
      1. 6.2.1 Application Circuits
    3. 6.3 Layout
      1. 6.3.1 Layout Guidelines
        1. 6.3.1.1 Printed Circuit Board Layout For High-Impedance Work
  8. 7Device and Documentation Support
    1. 7.1 Device Support
      1. 7.1.1 Development Support
        1. 7.1.1.1 Spice Macromodel
        2. 7.1.1.2 PSpice® for TI
        3. 7.1.1.3 TINA-TI™ Simulation Software (Free Download)
        4. 7.1.1.4 DIP-Adapter-EVM
        5. 7.1.1.5 DIYAMP-EVM
        6. 7.1.1.6 TI Reference Designs
        7. 7.1.1.7 Filter Design Tool
    2. 7.2 Receiving Notification of Documentation Updates
    3. 7.3 Support Resources
    4.     Trademarks
    5. 7.4 Electrostatic Discharge Caution
    6. 7.5 Glossary
  9. 8Revision History
  10. 9Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • D|14
Thermal pad, mechanical data (Package|Pins)
Orderable Information

6.2.1 Application Circuits

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Where: V0 = V1 + V2 − V3 – V4
(V1 + V2 ≥ (V3 + V4) to keep V0 > 0VDC
Figure 6-8 DC Summing Amplifier (VIN ≥ 0VDC and VO ≥ VDC
GUID-74006EF6-235D-4FE0-8889-278D0DD17A99-low.png
For
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(CMRR depends on this resistor ratio match)
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As shown: VO = 2(V2 − V1)
Figure 6-9 High Input Z, DC Differential Amplifier
GUID-89604E73-43B9-4246-A4CC-1716B88F589F-low.pngFigure 6-10 Photo Voltaic-Cell Amplifier
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If R1 = R5, R3 = R6, and R4 = R7; then
GUID-B4CFB040-9DF2-4D0C-A4A9-64118D85EEF9-low.png
∴AV ≈ 100 for circuit shown (R2 = 9.3k).
Figure 6-11 Instrumentation Amplifier
GUID-9C99F038-0258-4185-945F-B0091E7486D1-low.png
GUID-00961F58-09C5-480F-BE9F-CC5CA5AA15C2-low.pngFigure 6-12 Rail-to-Rail Single Supply Low Pass Filter

This low-pass filter circuit can be used as an antialiasing filter with the same supply as the ADC. Filter designs can also take advantage of the LMC649x ultra-low input current. The ultra-low input current yields negligible offset error even when large value resistors are used. This configuration in turn allows the use of smaller-valued capacitors that take up less board space and cost less.

GUID-179D29F8-A234-46C4-B0F8-D14717E39C21-low.pngFigure 6-13 Low Voltage Peak Detector with Rail-to-Rail Peak Capture Range

Dielectric absorption and leakage is minimized by using a polystyrene or polypropylene hold capacitor. The droop rate is primarily determined by the value of CHOLD and diode leakage current. Select low-leakage current diodes to minimize drooping.

GUID-B0795A37-EE7F-42A8-B2ED-D344BEC1646B-low.png
Rf = Rx
Rf >> R1, R2, R3, and R4
GUID-FD3B2113-8737-4331-AC97-7B03EC63A5C7-low.pngFigure 6-14 Pressure Sensor

In a manifold absolute pressure sensor application, a strain gauge is mounted on the intake manifold in the engine unit. Manifold pressure causes the sensing resistors, R1, R2, R3 and R4 to change. The resistors change in a way such that R2 and R4 increase by the same amount R1 and R3 decrease. This causes a differential voltage between the input of the amplifier. The gain of the amplifier is adjusted by Rf.