SLVS975C September   2009  – April 2018 TPS54318

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
      2.      Efficiency vs Output Current
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin 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 Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Fixed Frequency PWM Control
      2. 7.3.2  Slope Compensation and Output Current
      3. 7.3.3  Bootstrap Voltage (Boot) and Low Dropout Operation
      4. 7.3.4  Error Amplifier
      5. 7.3.5  Voltage Reference
      6. 7.3.6  Adjusting the Output Voltage
      7. 7.3.7  Enable and Adjusting Undervoltage Lockout
      8. 7.3.8  Soft-Start Pin
      9. 7.3.9  Sequencing
      10. 7.3.10 Constant Switching Frequency and Timing Resistor (RT/CLK Pin)
      11. 7.3.11 Overcurrent Protection
      12. 7.3.12 Frequency Shift
      13. 7.3.13 Reverse Overcurrent Protection
      14. 7.3.14 Synchronize Using the RT/CLK Pin
      15. 7.3.15 Power Good (PWRGD Pin)
      16. 7.3.16 Overvoltage Transient Protection
      17. 7.3.17 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Small Signal Model for Loop Response
      2. 7.4.2 Simple Small Signal Model for Peak Current Mode Control
      3. 7.4.3 Small Signal Model for Frequency Compensation
  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  Step One: Select the Switching Frequency
        2. 8.2.2.2  Step Two: Select the Output Inductor
        3. 8.2.2.3  Step Three: Choose the Output Capacitor
        4. 8.2.2.4  Step Four: Select the Input Capacitor
        5. 8.2.2.5  Step Five: Minimum Load DC COMP Voltage
        6. 8.2.2.6  Step Six: Choose the Soft-Start Capacitor
        7. 8.2.2.7  Step Seven: Select the Bootstrap Capacitor
        8. 8.2.2.8  Step Eight: Undervoltage Lockout Threshold
        9. 8.2.2.9  Step Nine: Select Output Voltage and Feedback Resistors
          1. 8.2.2.9.1 Output Voltage Limitations
        10. 8.2.2.10 Step 10: Select Loop Compensation Components
        11. 8.2.2.11 Power Dissipation Estimate
      3. 8.2.3 Application Curves
  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 Device Support
      1. 11.1.1 Custom Design With WEBENCH® Tools
      2. 11.1.2 Development 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

5 Pin Configuration and Functions

RTE Package
16 Pin WQFN
(TOP VIEW)
TPS54318 pinout_rte16_slvs974.gif

Pin Functions

PIN I/O(1) DESCRIPTION
NAME NO.
AGND 5 G Analog ground should be electrically connected to GND close to the device.
BOOT 13 I A bootstrap capacitor is required between BOOT and PH. If the voltage on this capacitor is below the minimum required by the BOOT UVLO, the output is forced to switch off until the capacitor is refreshed.
COMP 7 O Error amplifier output, and input to the output switch current comparator. Connect frequency compensation components to this pin.
EN 15 I Enable pin, internal pull-up current source. Pull below 1.2 V to disable. Float to enable. Can be used to set the on/off threshold (adjust UVLO) with two additional resistors.
GND 3 G Power ground. This pin should be electrically connected directly to the power pad under the device.
4
PH 10 O The source of the internal high-side power MOSFET, and drain of the internal low-side (synchronous) rectifier MOSFET.
11
12
PWRGD 14 O An open drain output, asserts low if output voltage is low due to thermal shutdown, overcurrent, over/under-voltage or EN shut down.
RT/CLK 8 I/O Resistor Timing or External Clock input pin.
SS 9 I/O Slow-start. An external capacitor connected to this pin sets the output voltage rise time. Soft
VIN 1 I Input supply voltage, 2.95 V to 6 V.
2
16
VSENSE 6 I Inverting node of the transconductance (gm) error amplifier.
Thermal Pad G GND pin should be connected to the exposed power pad for proper operation. This power pad should be connected to any internal PCB ground plane using multiple vias for good thermal performance.
(1) I = Input, O = Output, G = Ground