SNOSBY1C June   1999  – December 2015 LMC567

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 Recommended Operating Conditions
    3. 7.3 Thermal Information
    4. 7.4 Electrical Characteristics
    5. 7.5 Typical Characteristics
  8. 8 Parameter Measurement Information
    1. 8.1 Test Circuit
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Oscillator
      2. 9.3.2 Input
      3. 9.3.3 Loop Filter
      4. 9.3.4 Output Filter
      5. 9.3.5 Output
    4. 9.4 Device Functional Modes
      1. 9.4.1 Operation as LM567
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Timing Components
        2. 10.2.2.2 Bandwidth
        3. 10.2.2.3 Output Filter
        4. 10.2.2.4 Supply Decoupling
      3. 10.2.3 Application Curve
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 Development Support
    2. 13.2 Community Resources
    3. 13.3 Trademarks
    4. 13.4 Electrostatic Discharge Caution
    5. 13.5 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

10 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.

10.1 Application Information

These typical connection diagrams highlight the required external components and system level connections for proper operation of the device in several popular use cases.

Any design variation can be supported by TI through schematic and layout reviews. Visit support.ti.com for additional design assistance. Also, join the audio amplifier discussion forum at e2e.ti.com.

10.2 Typical Application

LMC567 00867001.png Figure 8. LMC567 Application Schematic

10.2.1 Design Requirements

For this design example, use the parameters listed in Table 2.

Table 2. Design Parameters

DESIGN PARAMETER EXAMPLE VALUE
Supply voltage 2 V to 9 V
Input voltage 20 mVRMS to (VCC + 0.5)
Input frequency 1 Hz to 500 KHz
Output current maximum 30 mA

10.2.2 Detailed Design Procedure

10.2.2.1 Timing Components

As VCO frequency (FOSC) runs at twice the frequency of the input tone, the desired input detection frequency can be defined by Equation 7:

Equation 7. LMC567 eq01_snosby1.gif

The central frequency of the oscillator is set by timing capacitor and resistor. The timing capacitor value (CT) must be set in order to calculate the timing resistor value (RT). This is given by Equation 8:

Equation 8. LMC567 eq02_snosby1.gif

So, in order to found the required component values to set the detection frequency Equation 9:

Equation 9. LMC567 eq03_snosby1.gif

This approximation is valid with lower frequencies; considerations must be taken when using higher frequencies. More information on this can be found in Oscillator.

10.2.2.2 Bandwidth

Detection bandwidth is represented as a percentage of FOSC. It can be approximated as a function of FOSC × C2 following the behavior indicated in Figure 4. More information on this can be found in Loop Filter.

10.2.2.3 Output Filter

The size of the output filter capacitor C1 is a tradeoff between slew rate and carrier ripple. More information on this can be found in Output Filter.

10.2.2.4 Supply Decoupling

The decoupling of supply pin 4 becomes more critical at high supply voltages with high operating frequencies, requiring C4 to be placed as close as possible to pin 4.

10.2.3 Application Curve

SPACE

LMC567 gr1_slvsbq4.gif Figure 9. Frequency Detection