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

2 Effects of Input Connections on AMC3301 Family Radiated Emissions

CISPR 11 peak measurements were performed with various input cable lengths and Texas Instruments’ AMC3301. The input cable lengths tested are a 1.5 m input, a 30 cm input and an input shorted at the input terminal of the evaluation module (EVM). The same AMC3301EVM was used for all tests and powered from an external battery. All measurements shown are in the horizontal, or worst-case, orientation. Refer to the test setups in Figure 2-1 and CISPR 11 radiated emissions EMI plots in Figure 2-2 and Figure 2-3.

Figure 2-1 Test setup with AMC3301EVM and Input Lengths

Figure 2-2 shows the radiated emissions performance of the AMC3301 with an input short shown in blue. The AMC3301 shows very little radiated emissions above the noise floor in red – demonstrating that the AMC3301 does not produce excessive radiated emissions if the input traces or cables to the device are short.

Figure 2-2 AMC3301EVM Input Short and Horizontal Ambient CISPR 11 Measurement

Figure 2-3 shows the radiated emissions measurement for the 1.5 m input in blue, 30 cm in red and input short in green. Longer input traces and cables connected to the AMC3301 increase the magnitude of radiated emissions as shown by the 1.5 m input and 30 cm input test cases compared to the input short.

Figure 2-3 AMC3301EVM with Different Input Lengths CISPR 11 Measurement