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

7.3.1 Current Limit

The device has an internal current-limit circuit that protects the regulator during transient high-load current faults or shorting events. In a high-load current fault, the current limit scheme limits the output current to the current limit (ICL). ICL is listed in the Electrical Characteristics table.

The output voltage is not regulated when the device is in current limit. When a current-limit event occurs, the device begins to heat up because of the increase in power dissipation. When the device is in current limit, the pass transistor dissipates power [(VI – VO) × ICL]. For more information on current limits, see the Know Your Limits application note.

To achieve a safe operation across a wide range of Input voltage, the UA78L series also has a built-in protection mechanism with current limit. The protection mechanism decreases the current limit as input-to-output voltage increases and keeps the power transistor inside a safe operating region for all values of input-to-output voltage. This protection is designed to provide some output current at all values of input-to-output voltage limits defined in the Recommended Operating ConditionsRecommended Operating ConditionsRecommended Operating ConditionsRecommended Operating ConditionsRecommended Operating ConditionsRecommended Operating ConditionsRecommended Operating Conditions table. Figure 7-1 shows the behavior of the current limit variation.

GUID-20230207-SS0I-TPVJ-PBQJ-RQS1XMVDG6ZT-low.svg Figure 7-1 Current-Limit vs VHead-room Behavior for New Chip Only