SLASFC6 August 2024 TAS2120
ADVANCE INFORMATION
The TAS2120 supports edge-rate control to minimize EMI, but the system designer may want to include passive devices on the Class-D output for further reduction in EMI . These passive devices that are labeled L2, L3, C10 and C11 in Section 7.2. If C10 and C11 are used, L2 and L3 must also be installed, and C10 and C11 must be placed after L2 and L3 respectively to maintain the stability of the output stage.
The component value selection for the EMI filters depends on the application need on the frequency band that needs to be suppressed using these filters. Higher cutoff frequency helps in reducing the BOM size and reduces the switching power loss associated with the filters. Application should select the highest cutoff frequency filter which will meet the system's frequency suppression target to get better efficiency performance.
The DC resistance of the inductors or ferrite beads used in the EMI filters also plays a critical role in system efficiency. Lower resistance reduces power loss and helps in improving overall system efficiency. Based on available board space, smallest DC resistance components which meet the application needs will give better efficiency performance.