SNVSBI5A July   2019  – September 2019 TPS3870-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Integrated Overvoltage Detection
      2.      Typical Overvoltage Accuracy Distribution
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Requirements
    7. 7.7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 VDD
      2. 8.3.2 SENSE
      3. 8.3.3 RESET
      4. 8.3.4 Capacitor Time (CT)
      5. 8.3.5 Manual Reset (MR)
    4. 8.4 Device Functional Modes
      1. 8.4.1 Normal Operation (VDD > VDD(MIN))
      2. 8.4.2 Undervoltage Lockout (VPOR < VDD < UVLO)
      3. 8.4.3 Power-On Reset (VDD < VPOR)
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Voltage Threshold Accuracy
      2. 9.1.2 CT Reset Time Delay
        1. 9.1.2.1 Factory-Programmed Reset Delay Timing
        2. 9.1.2.2 Programmable Reset Delay-Timing
      3. 9.1.3 RESET Latch Mode
      4. 9.1.4 Adjustable Voltage Thresholds
      5. 9.1.5 Immunity to SENSE Pin Voltage Transients
        1. 9.1.5.1 Hysteresis
    2. 9.2 Typical Application
      1. 9.2.1 Design 1: RESET Latch Mode
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curves
  10. 10Power Supply Recommendations
    1. 10.1 Power Supply Guidelines
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Nomenclature
    2. 12.2 Documentation Support
      1. 12.2.1 Evaluation Module
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

9.1.1 Voltage Threshold Accuracy

Voltage monitoring requirements vary depending on the voltage supply tolerance of the device being powered. Due to the high precision of the TPS3870-Q1 (±0.7% Max), the device allows for a wider supply voltage margins and threshold headroom for tight tolerance applications.

For example, take a DC/DC regulator providing power to a core voltage rail of an MCU. The MCU has a tolerance of ±5% of the nominal output voltage of the DC/DC. The user sets an ideal voltage threshold of 4% which allows for ±1% of threshold accuracy. Since the TPS3870-Q1 threshold accuracy is higher than ±1%, the user has more supply voltage margin which can allow for a relaxed power supply design. This gives flexibility to the DC/DC to use a smaller output capacitor or inductor because of a larger voltage window for voltage ripple and transients. There is also headroom between the minimum system voltage and voltage tolerance of the MCU to ensure that the voltage supply will never be in the region of potential failure of malfunction without the TPS3870-Q1 asserting a reset signal.

Figure 20 illustrates the supply overvoltage margin and accuracy of the TPS3870-Q1 for the example explained above. Using a low accuracy supervisor will eat into the available budget for the power supply ripple and transient response. This gives less flexibility to the user and a more stringent DC/DC converter design.

TPS3870-Q1 Power-supply-threshold-accuracy.gifFigure 20. TPS3870-Q1 Voltage Threshold Accuracy