SBVS425A december   2022  – may 2023 TPS748A-Q1

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
    6. 6.6 Typical Characteristics: IOUT = 50 mA
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Enable and Shutdown
      2. 7.3.2 Active Discharge
      3. 7.3.3 Power-Good Output (PG)
      4. 7.3.4 Internal Current Limit
      5. 7.3.5 Thermal Shutdown Protection (TSD)
    4. 7.4 Device Functional Modes
      1. 7.4.1 Normal Operation
      2. 7.4.2 Dropout Operation
      3. 7.4.3 Disabled
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Input, Output, and Bias Capacitor Requirements
      2. 8.1.2 Dropout Voltage
      3. 8.1.3 Output Noise
      4. 8.1.4 Estimating Junction Temperature
      5. 8.1.5 Soft Start, Sequencing, and Inrush Current
      6. 8.1.6 Power-Good 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 Example
  10. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

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

8.1.3 Output Noise

The TPS748A-Q1 provides low output noise when a soft-start capacitor is used. When the device reaches the end of the soft-start cycle, the soft-start capacitor serves as a filter for the internal reference. By using a 10-nF, soft-start capacitor, the output noise is reduced by half and is typically 7.1 μVRMS for a 0.8-V output (10 Hz to 100 kHz). Increasing CSS has no effect on noise. Because most of the output noise is generated by the internal reference, the noise is a function of the set output voltage. Equation 5 gives the RMS noise with a 10-nF, soft-start capacitor:

Equation 5. GUID-20220316-SS0I-XHBX-VWXD-TXH7DV8WX9W2-low.gif

The low output noise makes this LDO a good choice for powering transceivers, phase-locked loops (PLLs), or other noise-sensitive circuitry.