SLVS010X january   1976  – june 2023 UA78L

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Pin Configuration and Functions
  7. 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: UA78L02 (Legacy Chip Only)
    6. 6.6  Electrical Characteristics: UA78L033 (New Chip Only)
    7. 6.7  Electrical Characteristics: UA78L05 (Both Legacy and New Chip)
    8. 6.8  Electrical Characteristics: UA78L12 (Both Legacy and New Chip)
    9. 6.9  Electrical Characteristics: UA78L06 (Legacy Chip Only)
    10. 6.10 Electrical Characteristics: UA78L08 (Legacy Chip Only)
    11. 6.11 Electrical Characteristics: UA78L09 (Legacy Chip Only)
    12. 6.12 Electrical Characteristics: UA78L10 (Legacy Chip Only)
    13. 6.13 Electrical Characteristics: UA78L15 (Both Legacy and New Chip)
    14. 6.14 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Current Limit
      2. 7.3.2 Thermal Shutdown
      3. 7.3.3 Dropout Voltage (VDO)
    4. 7.4 Device Functional Modes
      1. 7.4.1 Normal Operation
      2. 7.4.2 Dropout Operation
  9. 8 Applications 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
        1. 8.2.2.1 Input and Output Capacitor Requirements
        2. 8.2.2.2 Power Dissipation (PD)
        3. 8.2.2.3 Estimating Junction Temperature
        4. 8.2.2.4 External Capacitor Requirements
        5. 8.2.2.5 Overload Recovery
        6. 8.2.2.6 Reverse Current
        7. 8.2.2.7 Polarity Reversal Protection
      3. 8.2.3 Application Curves
    3. 8.3 System Examples
      1. 8.3.1 Positive Regulator in Negative Configuration
      2. 8.3.2 Current Limiter Circuit
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
      2. 8.5.2 Layout Example
  10. 9 Device 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 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • D|8
  • PK|3
  • LP|3
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.4.2 Dropout Operation

If the input voltage is lower than the nominal output voltage plus the specified dropout voltage, but all other conditions are met for normal operation, the device operates in dropout mode. In this mode, the output voltage tracks the input voltage. During this mode, the transient performance of the device becomes significantly degraded because the pass transistor is in the ohmic or triode region, and acts as a switch. Line or load transients in dropout can result in large output voltage deviations.

When the device is in a steady dropout state (defined as when the device is in dropout, VI < VOUT(NOM) + VDO, directly after being in a normal regulation state, but not during start up), the pass transistor is driven into the ohmic or triode region. When the input voltage returns to a value greater than or equal to the nominal output voltage plus the dropout voltage (VOUT(NOM) + VDO), the output voltage can overshoot for a short period of time while the device pulls the pass transistor back into the linear region.