SNVU588A December   2017  – January 2022 TPS40345

 

  1.   Trademarks
  2. 1Description
    1. 1.1 Applications
    2. 1.2 Features
  3. 2TPS40345EVM-353 Electrical Performance Specifications
  4. 3TPS40345EVM-353 Schematic
  5. 4Connector and Test Point Descriptions
    1. 4.1 Enable Jumper (JP2)
    2. 4.2 Frequency Spread Spectrum – FSS Jumper (JP1)
    3. 4.3 Test Point Descriptions
      1. 4.3.1 Input Voltage Monitoring (TP1 and TP2)
      2. 4.3.2 Output Voltage Monitoring (TP3 and TP4)
      3. 4.3.3 Loop Response Testing (TP5, TP6, TP7, TP8, and R3)
      4. 4.3.4 Error Amplifier Voltage Monitoring (TP9, TP10, and TP11)
      5. 4.3.5 Switching Waveform Monitoring (TP12, TP13, TP14, and TP15)
      6. 4.3.6 Power-Good Voltage Monitoring (TP16 and TP18)
      7. 4.3.7 Enable and Soft-Start Voltage Monitoring (TP17 and TP18)
  6. 5Test Setup
    1. 5.1 Equipment
      1. 5.1.1 Voltage Source
      2. 5.1.2 Meters
      3. 5.1.3 Load
      4. 5.1.4 Oscilloscope
      5. 5.1.5 Recommended Wire Gauge
      6. 5.1.6 Other
    2. 5.2 Equipment Setup
      1. 5.2.1 Procedure
      2. 5.2.2 Diagram
    3. 5.3 Start-Up/Shutdown Procedure
    4. 5.4 Output Ripple Voltage Measurement Procedure
    5. 5.5 Control Loop Gain and Phase Measurement Procedure
    6. 5.6 Equipment Shutdown
  7. 6TPS40345EVM-353 Test Data
    1. 6.1 Efficiency
    2. 6.2 Line and Load Regulation
    3. 6.3 Output Voltage Ripple
    4. 6.4 Switch Node
    5. 6.5 Control Loop Bode Diagram
    6. 6.6 Additional Waveforms
      1. 6.6.1 Output Ripple With Frequency Spread Spectrum (FSS) Enabled
  8. 7TPS40345EVM-353 Assembly Drawings and Layout
  9. 8TPS40345EVM-353 Bill of Materials
  10. 9Revision History

4.2 Frequency Spread Spectrum – FSS Jumper (JP1)

The TPS40345EVM-353 is designed with a frequency spread spectrum (FSS) enable jumper (JP1) using a 0.1-inch spacing header and shunt. Installing a shunt in the JP1 position connects the EN/SS pin to BP via a 267-kΩ resistor (R10) to enable frequency spread spectrum.

FSS modulates the switching frequency to ±10% of the nominal value at 30 kHz to reduce EMI at the switching frequency and its harmonics, however there may be a 30-kHz component to the output ripple (see Figure 6-6).

The TPS40345EVM-353 does not dynamically monitor the JP1 status for programming FSS. The TPS40345EVM-353 must be disabled via JP2 or powered down by reducing VIN to less than 3 V to remove or install JP1.