SLVS638C January   2006  – November 2014


  1. Features
  2. Applications
  3. Description
  4. Functional Block Diagram
  5. Revision History
  6. Pin Configuration and Functions
  7. Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 Handling Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics — TL2575
    6. 7.6 Electrical Characteristics — TL2575HV
    7. 7.7 Typical Characteristics
  8. Parameter Measurement Information
    1. 8.1 Test Circuits
  9. Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Feedback Connection
      2. 9.3.2 ON/OFF Input
    4. 9.4 Device Functional Modes
      1. 9.4.1 Standby Mode
  10. 10Application and Implementation
    1. 10.1 Typical Application
      1. 10.1.1 Design Requirements
      2. 10.1.2 Detailed Design Procedure
        1. Input Capacitor (CIN)
        2. Output Capacitor (COUT)
        3. Catch Diode
        4. Inductor
        5. Output Voltage Ripple and Transients
        6. Grounding
        7. Reverse Current Considerations
        8. Buck Regulator Design Procedure
        9. Inductor Selection Guide
      3. 10.1.3 Application Curves
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Related Links
    2. 13.2 Trademarks
    3. 13.3 Electrostatic Discharge Caution
    4. 13.4 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

9 Detailed Description

9.1 Overview

The TL2575 and TL2575HV devices greatly simplify the design of switching power supplies by conveniently providing all the active functions needed for a step-down (buck) switching regulator in an integrated circuit. Accepting a wide input-voltage range of up to 60 V (TL2575-HV) and available in fixed output voltages of 3.3 V, 5 V, 12 V, 15 V, or an adjustable-output version, the TL2575 and TL2575HV devices have an integrated switch capable of delivering 1 A of load current, with excellent line and load regulation. The device also offers internal frequency compensation, a fixed-frequency oscillator, cycle-by-cycle current limiting, and thermal shutdown. In addition, a manual shutdown is available via an external ON/OFF pin.

The TL2575 and TL2575HV devices represent superior alternatives to popular three-terminal linear regulators. Due to their high efficiency, the devices significantly reduce the size of the heatsink and, in many cases, no heatsink is required. Optimized for use with standard series of inductors available from several different manufacturers, the TL2575 and TL2575HV greatly simplify the design of switch-mode power supplies by requiring a minimal addition of only four to six external components for operation.

The TL2575 and TL2575HV devices are characterized for operation over the virtual junction temperature range of –40°C to 125°C.

9.2 Functional Block Diagram

Pin numbers are for the KTT (TO-263) package.

9.3 Feature Description

9.3.1 Feedback Connection

For fixed-voltage options, FEEDBACK must be wired to VOUT. For the adjustable version, FEEDBACK must be connected between the two programming resistors. Again, both of these resistors should be in close proximity to the regulator, and each should be less than 100 kΩ to minimize noise pickup.

9.3.2 ON/OFF Input

ON/OFF should be grounded or be a low-level TTL voltage (typically < 1.6 V) for normal operation. To shut down the TL2575 or TL2575HV devices and place in standby mode, a high-level TTL or CMOS voltage should be supplied to this pin. ON/OFF should not be left open and safely can be pulled up to VIN with or without a pullup resistor.

9.4 Device Functional Modes

9.4.1 Standby Mode

When a high-level TTL or CMOS voltage is applied to the ON/OFF pin, the device enters standby mode, drawing a typical quiescent current of 50 µA.