SBAA515A June   2021  – September 2022 AMC3301 , AMC3301-Q1 , AMC3302 , AMC3302-Q1 , AMC3306M05 , AMC3306M25 , AMC3330 , AMC3330-Q1 , AMC3336 , AMC3336-Q1

 

  1.   Abstract
  2.   Trademarks
  3. 1Introduction
  4. 2Effects of Input Connections on AMC3301 Family Radiated Emissions
  5. 3Attenuating AMC3301 Family Radiated Emissions
    1. 3.1 Ferrite Beads and Common Mode Chokes
    2. 3.2 PCB Schematics and Layout Best Practices for AMC3301 Family
  6. 4Using Multiple AMC3301 Devices
    1. 4.1 Device Orientation
    2. 4.2 PCB Layout Best Practices for Multiple AMC3301
  7. 5Conclusion
  8. 6AMC3301 Family Table
  9. 7Revision History

3.2 PCB Schematics and Layout Best Practices for AMC3301 Family

Figure 3-3 shows the schematic for the ferrite beads on the left and the common-mode choke on the right. Note that three ferrite beads are required, one for each input as well as one for the HGND trace to the shunt resistor. The common-mode choke has two channels and terminating the HGND connection to VINN near the common-mode choke is necessary. The differential RC filter created by R2, R4 and C12 is placed between the ferrite beads or common-mode choke and the AMC3301. Refer to the layout guidelines section in the device’s data sheet for additional detail.

Figure 3-3 AMC3301 Ferrite Bead and Common-mode Choke Schematics

The ferrite beads or common-mode choke should be placed as close to the device as possible to limit the amount of copper area that will act as an antenna. A direct and low inductance connection should be made from pin 2 (DCDC_HGND) to pin 8 (HGND). Figure 3-4 shows the recommended layouts for the ferrite beads on the left and the common-mode choke on the right.

Figure 3-4 AMC3301 Ferrite Bead and Common-mode Choke Layouts