SLUUCR2 October   2023 TPSM843620

 

  1.   1
  2.    TPSM843620EVM 6-A, SWIFT™ Regulator Evaluation Module
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Background
    2. 1.2 Before You Begin
    3. 1.3 Performance Characteristics Summary
  5. 2Configurations and Modifications
    1. 2.1 Output Voltage
    2. 2.2 Switching Frequency (SYNC/FSEL Pin)
    3. 2.3 Current Limit, Soft-Start Time, and Internal Compensation (MODE Pin)
    4. 2.4 Adjustable UVLO
  6. 3Test Setup and Results
    1. 3.1  Input/Output Connections
    2. 3.2  BOM Modifications for Spins
    3. 3.3  Efficiency
    4. 3.4  Output Voltage Regulation
    5. 3.5  Load Transient and Loop Response
    6. 3.6  Output Voltage Ripple
    7. 3.7  Input Voltage Ripple
    8. 3.8  Start-up and Shutdown with EN
    9. 3.9  Start-up and Shutdown with VIN
    10. 3.10 Start-up Into Pre-Bias
    11. 3.11 Thermal Performance
  7. 4Board Layout
    1. 4.1 Layout
  8. 5Schematic and Bill of Materials
    1. 5.1 Schematic
    2. 5.2 Bill of Materials

4.1 Layout

The board layout for the TPSM843620EVM is shown in Figure 4-1 through Figure 4-6. The top-side layer of the EVM is laid out in a manner typical of a user application. The top, bottom, and internal layers are 2-oz. copper. The small size circuit takes up an area of only approximately 115 mm2 as shown on the silkscreen.

All of the required components for the TPSM843620 are placed on the top layer. The input decoupling capacitors, BP5 capacitor, and bootstrap capacitor are all located as close to the IC as possible. Additionally, the voltage set point resistor divider components are kept close to the IC. An additional input bulk capacitor is used near the input terminal to limit the noise entering the converter from the supply used to power the board. Critical analog circuits such as the voltage set point divider, MODE resistor, EN divider, and FSEL resistor are kept close to the IC and terminated to the quiet analog ground (AGND) island on the top layer.

The top layer contains the main power traces for VIN and VOUT. The top layer power traces are connected to the planes on other layers of the board with multiple vias placed around the board. There are multiple vias near the PGND pins of the IC to help maximize the thermal performance. The TPSM843620 circuit has a dedicated ground for quiet analog ground that is connected to the main power ground plane at a single point. Lastly, the voltage divider network ties to the output voltage at the point of regulation, the copper VOUT area on the top layer.

The mid layer 1 is a large ground plane with as few traces as possible to minimize cuts in the ground plane. The mid layer 1 is important to minimize cuts in the ground plane near the IC to help with minimize noise and maximize thermal performance.

The mid layer 2 is mainly used as a signal layer. This layer also has the trace to connect the FB divider to the output. There is also a trace for the BP5 signal to be connected to the buffer. Lastly, the remaining area of this layer is filled in with PGND.

The bottom layer is primarily used for another ground plane. This layer also has an additional VOUT copper area.

GUID-20231016-SS0I-GMBL-LNPW-DQHQLPQJT62V-low.pngFigure 4-1 Top-Side Composite View
GUID-20230922-SS0I-XQZQ-FZDF-LH3VKDMKTJCC-low.gifFigure 4-3 Top Layer Layout
GUID-20230922-SS0I-X1S5-19KV-8CHGNNG1NJJC-low.gifFigure 4-5 Mid Layer 2 Layout
GUID-20230922-SS0I-JC4N-FT4B-QWP7JKP2TMGJ-low.gifFigure 4-2 Bottom-Side Composite View (Viewed From Bottom)
GUID-20230922-SS0I-TDDQ-9BWD-LC0VRBDFCZPM-low.gifFigure 4-4 Mid Layer 1 Layout
GUID-20230922-SS0I-SCM1-S1M9-T21VTSCRX4WF-low.gifFigure 4-6 Bottom Layer Layout