SNVS233C March   2003  – December 2015 LM8365

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
    4. 7.4 Device Functional Modes
      1. 7.4.1 Reset Output Low
      2. 7.4.2 Reset Output High
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curves
    3. 8.3 System Examples
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Device Nomenclature
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

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8 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.

8.1 Application Information

The LM8365 is a supervisor that is ideal for use in battery powered microprocessor based systems. With an external delay capacitor, CD, a time delay can be accurately programmed to allow for use in many types of applications. The LM8365 can ensure system reliability and ensures that a connected microprocessor will operate only when a minimum VIN supply is satisfied.

8.2 Typical Application

The LM8365 can be used as a simple supervisor circuit to monitor the input supply to a microprocessor as shown in Figure 14.

LM8365 20066018.gif Figure 14. Microprocessor Reset Circuit

8.2.1 Design Requirements

For this design example, use the parameters listed in Table 1 as the input parameters.

Table 1. Design Parameters

DESIGN PARAMETER EXAMPLE VALUE
Input Supply voltage range 1 V to 6 V
Reset Output voltage, high Input Supply
Reset Output voltage, low 0 V
Output Time delay, CD = 0.1 μF 130 ms
Output Time delay, CD = 1 μF 1.2 s

8.2.2 Detailed Design Procedure

The Bill of Materials shown in Table 2 reflects the components used on the LM8365EVM. A layout of the EVM can be seen in Figure 19.

Table 2. Bill of Materials

DESIGNATOR DESCRIPTION PART NUMBER QUANTITY MANUFACTURER
U1 LM8365, 2.7V Threshold LM8365 1 Texas Instruments
R1 470K Resistor, 0603 CRCW0603470KJNEA 1 Vishay
C1 0.01μF Capacitor, 0603 GRM188R71C103KA01D 1 MuRata
C2 0.1μF Capacitor, 0805 GRM219R71C104KA01D 1 MuRata
C3 1μF Capacitor, 0805 C0805C105K4RACTU 1 Kemet
C4 Input Capacitor – 0 –

8.2.3 Application Curves

Two capacitor values for CD (0.1 μF and 1 μF) are used as examples to show the programmability of the output time delay as shown in Figure 15 and Figure 16.

LM8365 app_curve_1_SNVS233.gif
Figure 15. 0.1-μF Capacitor Programmed Delay
LM8365 app_curve_2_SNVS233.gif Figure 16. 1-μF Capacitor Programmed Delay

8.3 System Examples

The LM8365 can be used as a missing pulse detector. As shown in Figure 17, if a high-to-low transition pulse were to be missing, the CD voltage would continue to increase until it reaches its threshold of 0.675 × VIN, causing the Reset pin to output high and signal a missing pulse.

LM8365 20066020.gif Figure 17. Missing Pulse Detector Using LM8365BALMF45