SNVSBJ2A April   2022  – September 2023 TPS38

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Device Comparison
  7. 6 Pin Configuration and Functions
    1.     8
  8. 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 Timing Diagrams
    8. 7.8 Typical Characteristics
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Input Voltage (VDD)
        1. 8.3.1.1 Undervoltage Lockout (VPOR < VDD < UVLO)
        2. 8.3.1.2 Power-On Reset (VDD < VPOR )
      2. 8.3.2 SENSE
        1. 8.3.2.1 SENSE Hysteresis
      3. 8.3.3 Output Logic Configurations
        1. 8.3.3.1 Open-Drain
        2. 8.3.3.2 Push-Pull
        3. 8.3.3.3 Active-High (RESET)
        4. 8.3.3.4 Active-Low (RESET)
      4. 8.3.4 User-Programmable Reset Time Delay
        1. 8.3.4.1 Reset Time Delay Configuration
      5. 8.3.5 User-Programmable Sense Delay
        1. 8.3.5.1 Sense Time Delay Configuration
      6. 8.3.6 Manual RESET (CTR1 / MR) and (CTR2 / MR) Input
      7. 8.3.7 Adjustable Voltage Thresholds
    4. 8.4 Device Functional Modes
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 High Voltage – Fast AC Signal Monitoring For Power Fault Detection
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curves
    3. 9.3 Power Supply Recommendations
      1. 9.3.1 Power Dissipation and Device Operation
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
      3. 9.4.3 Creepage Distance
  11. 10Device and Documentation Support
    1. 10.1 Device Nomenclature
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary

Package Options

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

8.3.2.1 SENSE Hysteresis

The TPS38 has built-in hysteresis to avoid erroneous output reset release. The hysteresis is opposite to the threshold voltage; for overvoltage options the hysteresis is subtracted from the positive threshold (VITP), for undervoltage options hysteresis is added to the negative threshold (VITN).
GUID-20200819-CA0I-SBQM-CC4P-F9SF3V4TNH0P-low.gifFigure 8-4 Hysteresis (Overvoltage Active-Low)
GUID-20200819-CA0I-RLTT-BDP1-NTJWPJBD6W9T-low.gifFigure 8-6 Hysteresis (Undervoltage Active-High)
GUID-20200819-CA0I-JRJW-KDX8-FSS17LCPFF2V-low.gifFigure 8-5 Hysteresis (Overvoltage Active-High)
GUID-20200819-CA0I-WK8H-XNTM-PCK0BKLBVN67-low.gifFigure 8-7 Hysteresis (Undervoltage Active-Low)
Table 8-1 Common Hysteresis Lookup Table
TARGET DEVICE ACTUAL HYSTERESIS OPTION
DETECT THRESHOLD TOPOLOGY RELEASE VOLTAGE (V)
18.0 V Overvoltage 17.5 V -3%
18.0 V Overvoltage 16.0 V -11%
17.0 V Overvoltage 16.5 V -3%
16.0 V Overvoltage 15.0 V -6%
15.0 V Overvoltage 14.0 V -7%
6.0 V Undervoltage 6.5 V 0.5 V
5.5 V Undervoltage 6 V 0.5 V
8 V Undervoltage 9 V 1 V
5 V Undervoltage 7.5 V 2.5 V

Table 8-1 shows a sample of hysteresis and voltage options for the TPS38. For threshold voltages ranging from 2.7 V to 8 V, one option is to select a fixed hysteresis value ranging from 0.5 V to 2.5 V in increments of 0.5 V. Additionally, a second option can be selected where the hysteresis value is a percentage of the threshold voltage. The percentage of voltage hysteresis ranges from 2% to 13%.

Knowing the amount of hysteresis voltage, the release voltage for the undervoltage (UV) channel is
(VITN(UV) + VHYS) and for the overvoltage (OV) channel is (VITP(OV) - VHYS). For a visual understanding of the UV and OV release voltage, see Figure 7-2 and Figure 7-3 . The accuracy of the release voltage, or stated in the Section 7.5 as Hysteresis Accuracy is ±1.5%. Expanding what is shown in Table 8-1, below are a few voltage hysteresis examples that include the hysteresis accuracy:

Undervoltage (UV) Channel

VITN = 0.8 V

Voltage Hysteresis (VHYS) = 5% = 40 mV

Hysteresis Accuracy = ±1.5% = 39.4 mV or 40.6 mV

Release Voltage = VITN + VHYS = 839.4 mV to 840.6 mV

Overvoltage (OV) Channel

VITP = 8 V

Voltage Hysteresis (VHYS) = 2 V

Hysteresis Accuracy = ±1.5% = 1.97 V or 2.03 V

Release Voltage = VITP − VHYS = 5.97 V to 6.03V