SLVS338R May   2001  – April 2015 TPS715

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 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
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
      1. 7.3.1 Wide Supply Range
      2. 7.3.2 Low Supply Current
      3. 7.3.3 Stable With Any Capacitor ≥ 0.47 µF
      4. 7.3.4 Internal Current Limit
      5. 7.3.5 Reverse Current
    4. 7.4 Device Functional Modes
      1. 7.4.1 Normal Operation
      2. 7.4.2 Dropout Operation
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
        1. 8.2.1.1 Power the MSP430 Microcontroller
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 External Capacitor Requirements
        2. 8.2.2.2 Dropout Voltage (VDO)
        3. 8.2.2.3 Setting VOUT for the TPS71501 Adjustable LDO
      3. 8.2.3 Application Curves
    3. 8.3 Do's and Don'ts
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Power Dissipation
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
        1. 11.1.1.1 Evaluation Module
        2. 11.1.1.2 Spice Models
      2. 11.1.2 Device Nomenclature
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7 Detailed Description

7.1 Overview

The TPS715 family of LDOs consume only 3.2 µA of current while offering a wide input voltage range and low-dropout voltage in a small package. The devices, which operate over an input range of 2.5 V to 24 V, are stable with any capacitor greater than or equal to 0.47 μF. The low quiescent current makes the TPS715 ideal for powering battery management ICs. Specifically, because the TPS715 is enabled as soon as the applied voltage reaches the minimum input voltage, the output is quickly available to power continuously operating battery charging ICs.

7.2 Functional Block Diagrams

TPS715 fbd_adj_lvs338.gifFigure 10. Functional Block Diagram—Adjustable Version
TPS715 fbd_fix_lvs338.gifFigure 11. Functional Block Diagram—Fixed Version

7.3 Feature Description

7.3.1 Wide Supply Range

This device has an operational input supply range of 2.5 V to 24 V, allowing for a wide range of applications. This wide supply range is ideal for applications that have either large transients or high DC voltage supplies.

7.3.2 Low Supply Current

This device only requires 3.2 µA (typical) of supply current from –40°C to 85°C and has a maximum current consumption of 5.8 µA at –40°C to 125°C.

7.3.3 Stable With Any Capacitor ≥ 0.47 µF

Any capacitor, including both ceramic and tantalum, greater than or equal to 0.47 μF properly stabilizes this loop.

7.3.4 Internal Current Limit

The internal current limit circuit is used to protect the LDO against high-load current faults or shorting events. The LDO is not designed to operate in a steady-state current limit. During a current limit event, the LDO sources constant current. Therefore, the output voltage falls when load impedance decreases.

NOTE

if a current limit occurs and the resulting output voltage is low, excessive power is dissipated across the LDO, resulting in possible damage to the device.

7.3.5 Reverse Current

The TPS715 PMOS-pass transistor has a built-in back diode that conducts current when the input voltage drops below the output voltage (for example, during power down). Current is conducted from the output to the input and is not internally limited. If extended reverse voltage operation is anticipated, external limiting may be required.

7.4 Device Functional Modes

Table 1 provides a quick comparison between the normal, dropout, and disabled modes of operation.

Table 1. Device Functional Mode Comparison

OPERATING MODE PARAMETER
VIN IOUT
Normal VIN > VOUT(nom) + VDO IOUT < ICL
Dropout VIN < VOUT(nom) + VDO IOUT < ICL
Disabled — —

7.4.1 Normal Operation

The device regulates to the nominal output voltage under the following conditions:

  • The input voltage is greater than the nominal output voltage plus the dropout voltage (VOUT(nom) + VDO).
  • The output current is less than the current limit (IOUT < ICL).
  • The device junction temperature is less than 125°C.

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 device is in the linear region and no longer controls the current through the LDO. Line or load transients in dropout can result in large output-voltage deviations.