SBVS400D december   2021  – august 2023 TPS7A14

PRODUCTION DATA  

  1.   1
  2. 1Features
  3. 2Applications
  4. 3Description
  5. 4Revision History
  6. 5Pin Configuration and Functions
  7. 6Specifications
    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 Switching Characteristics
    7. 6.7 Typical Characteristics
  8. 7Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Excellent Transient Response
      2. 7.3.2 Global Undervoltage Lockout (UVLO)
      3. 7.3.3 Enable Input
      4. 7.3.4 Internal Foldback Current Limit
      5. 7.3.5 Active Discharge
      6. 7.3.6 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Normal Operation
      2. 7.4.2 Dropout Operation
      3. 7.4.3 Disable Mode
  9. 8Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1  Recommended Capacitor Types
      2. 8.1.2  Input, Output, and Bias Capacitor Requirements
      3. 8.1.3  Dropout Voltage
      4. 8.1.4  Behavior During Transition From Dropout Into Regulation
      5. 8.1.5  Device Enable Sequencing Requirement
      6. 8.1.6  Load Transient Response
      7. 8.1.7  Undervoltage Lockout Circuit Operation
      8. 8.1.8  Power Dissipation (PD)
      9. 8.1.9  Estimating Junction Temperature
      10. 8.1.10 Recommended Area for Continuous Operation
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curve
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Examples
  10. 9Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Development Support
        1. 9.1.1.1 Evaluation Module
      2. 9.1.2 Device Nomenclature
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Glossary
  11.   Mechanical, Packaging, and Orderable Information
    1. 10.1 Mechanical Data

Package Options

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

8.1.3 Dropout Voltage

Dropout voltage (VDO) is defined as the input voltage minus the output voltage (VIN – VOUT) at the rated output current (IRATED), where the pass transistor is fully on. IRATED is the maximum IOUT listed in the Recommended Operating ConditionsRecommended Operating ConditionsRecommended Operating ConditionsRecommended Operating ConditionsRecommended Operating Conditions table. The pass transistor is in the ohmic or triode region of operation, and acts as a switch. The dropout voltage indirectly specifies a minimum input voltage greater than the nominal programmed output voltage at which the output voltage is expected to stay in regulation. If the input voltage falls to less than the nominal output regulation, then the output voltage falls as well.

For a CMOS regulator, the dropout voltage is determined by the drain-source on-state resistance (RDS(ON)) of the pass transistor. Therefore, if the linear regulator operates at less than the rated current, the dropout voltage for that current scales accordingly. Use Equation 1 to calculate the RDS(ON) of the device.

Equation 1. GUID-22DC56F4-8451-450E-81EC-67220BBFFCB4-low.gif

The use of bias rail enables the TPS7A14 to achieve a lower dropout voltage between IN and OUT. However, a minimum bias voltage above the nominal programmed output voltage must be maintained. Figure 6-13 specifies the minimum VBIAS headroom required to maintain output regulation.