SLVSAL1E March   2011  – April 2016 TPS24720

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 THERMAL INFORMATION
    4. 6.4 Recommended Operating Conditions
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Detailed Pin Descriptions
        1. 7.3.1.1  EN
        2. 7.3.1.2  ENSD
        3. 7.3.1.3  FFLTb
        4. 7.3.1.4  FLTb
        5. 7.3.1.5  GATE
        6. 7.3.1.6  GND
        7. 7.3.1.7  IMON
        8. 7.3.1.8  LATCH
        9. 7.3.1.9  OUT
        10. 7.3.1.10 OV
        11. 7.3.1.11 PGb
        12. 7.3.1.12 PROG
        13. 7.3.1.13 SENSE
        14. 7.3.1.14 SET
        15. 7.3.1.15 TIMER
        16. 7.3.1.16 VCC
    4. 7.4 Device Functional Modes
      1. 7.4.1  Board Plug-In
      2. 7.4.2  Inrush Operation
      3. 7.4.3  Action of the Constant-Power Engine
      4. 7.4.4  Circuit Breaker and Fast Trip
      5. 7.4.5  Automatic Restart
      6. 7.4.6  PGb, FLTb, and Timer Operations
      7. 7.4.7  Overtemperature Shutdown
      8. 7.4.8  Start-Up of Hot-Swap Circuit by VCC or EN
      9. 7.4.9  Minimization of Power Dissipation at STANDY by ENSD
      10. 7.4.10 Fault Detection of MOSFET Short With FFLTb
  8. 8 Application 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 Power-Limited Start-Up
          1. 8.2.2.1.1 STEP 1. Choose RSENSE, RSET, and RIMON
          2. 8.2.2.1.2 STEP 2. Choose MOSFET M1
          3. 8.2.2.1.3 STEP 3. Choose Power-Limit Value, PLIM, and RPROG
          4. 8.2.2.1.4 STEP 4. Choose Output Voltage Rising Time, tON, and Timing Capacitor CT
          5. 8.2.2.1.5 STEP 5. Calculate the Retry-Mode Duty Ratio
          6. 8.2.2.1.6 STEP 6. Select R1, R2, and R3 for UV and OV
          7. 8.2.2.1.7 STEP 7. Choose RGATE, R4, R5, R6, and C1
        2. 8.2.2.2 Additional Design Considerations
          1. 8.2.2.2.1 Use of PGb
          2. 8.2.2.2.2 Output Clamp Diode
          3. 8.2.2.2.3 Gate Clamp Diode
          4. 8.2.2.2.4 High-Gate-Capacitance Applications
          5. 8.2.2.2.5 Bypass Capacitors
          6. 8.2.2.2.6 Output Short-Circuit Measurements
      3. 8.2.3 Application Curve
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
    2. 11.2 Trademarks
    3. 11.3 Electrostatic Discharge Caution
    4. 11.4 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

10 Layout

10.1 Layout Guidelines

TPS24720 applications require careful attention to layout to ensure proper performance and to minimize susceptibility to transients and noise. In general, all traces should be as short as possible, but the following list deserves first consideration:

  • Decoupling capacitors on VCC pin should have minimal trace lengths to the pin and to GND.
  • Traces to SET and SENSE must be short and run side-by-side to maximize common-mode rejection. Kelvin connections should be used at the points of contact with RSENSE (see Figure 40).
  • SET runs must be short on both sides of RSET.
  • Power path connections should be as short as possible and sized to carry at least twice the full-load current, more if possible.
  • Connections to GND and IMON pins should be minimized after the previously described connections have been placed.
  • The device dissipates low power, so soldering the thermal pad to the board is not a requirement. However, doing so improves thermal performance and reduces susceptibility to noise.
  • Protection devices such as snubbers, TVS, capacitors, or diodes should be placed physically close to the device they are intended to protect, and routed with short traces to reduce inductance. For example, the protection Schottky diode shown in the typical application diagram on the front page of the data sheet should be physically close to the OUT pin.

10.2 Layout Example

TPS24720 M0217-01_LVSAL1.gif Figure 40. Recommended RSENSE Layout