SBVS141D April   2010  – December 2023 TPS74701-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Typical Characteristics: IOUT = 50 mA
    7. 5.7 Typical Characteristics: VEN = VIN = 1.8 V, VOUT = 1.5 V
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Transient Response
      2. 6.3.2 Dropout Voltage
      3. 6.3.3 Output Noise
      4. 6.3.4 Enable and Shutdown
      5. 6.3.5 Power Good
      6. 6.3.6 Internal Current Limit
      7. 6.3.7 Thermal Protection
    4. 6.4 Device Functional Modes
      1. 6.4.1 Normal Operation
      2. 6.4.2 Dropout Operation
      3. 6.4.3 Disabled
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Input, Output, and Bias Capacitor Requirements
        2. 7.2.2.2 Programmable Soft-Start
        3. 7.2.2.3 Sequencing Requirements
      3. 7.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
        1. 7.4.1.1 Layout Recommendations and Power Dissipation
        2. 7.4.1.2 Estimating Junction Temperature
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Development Support
      2. 8.1.2 Device Nomenclature
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

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

6.3.2 Dropout Voltage

The TPS74701-Q1 offers very low dropout performance, making the device designed for high-current, low VIN, low VOUT applications. The low dropout of the TPS74701-Q1 allows the device to be used in place of a DC/DC converter and still achieve good efficiency. This feature provides designers with the power architecture for their applications to achieve the smallest, simplest, and lowest cost solution.

There are two different specifications for dropout voltage with the TPS74701-Q1. The first specification (shown in Figure 6-1) is referred to as VIN dropout and is used when an external bias voltage is applied to achieve low dropout. This specification assumes that VBIAS is at least 1.62 V above VOUT, which is the case for VBIAS when powered by a 3.3-V rail with 5% tolerance and with VOUT = 1.5 V. If VBIAS is higher than VOUT + 1.62 V, VIN dropout is less than specified.

GUID-54750128-2AEB-4498-84CF-F2E0C95B3083-low.gifFigure 6-1 Typical Application of the TPS74701-Q1 Using an Auxiliary Bias Rail

The second specification (shown in Figure 6-2) is referred to as VBIAS dropout and applies to applications where IN and BIAS are tied together. This option allows the device to be used in applications where an auxiliary bias voltage is not available or low dropout is not required. Dropout is limited by BIAS in these applications because VBIAS provides the gate drive to the pass transistor; therefore, VBIAS must be 1.39 V above VOUT for the legacy chip or 1.3 V for the new chip(1). Because of this usage, IN and BIAS tied together easily consume huge power. Pay attention not to exceed the power rating of the device package.

GUID-4361B792-D669-41BB-8306-70FA0228B0BD-low.gifFigure 6-2 Typical Application of the TPS74701-Q1 Without an Auxiliary Bias Rail
1. See the Device Nomenclature and Electrical Characteristics for more information regarding the legacy chip and new chip