8.2.2.5.3 Driver Slew Rate Control

Figure 30 shows the high current driver outputs with independent source and current sink pins for slew rate control. Slew rate control enables the user to adjust the switch node rise and fall times which can reduce the conducted EMI in the FM radio band (30 MHz to 108 MHz). Using the LM25141-Q1 EVM, conducted emissions were measured in accordance with CISPR 25 Class 5. Figure 31 shows the measured results without slew rate control.

The conducted EMI results with slew rate control are shown in Figure 32, a 10-dB reduction in conduction emissions in the FM band is attained by using slew rate control. This can help reduce the size and cost of the EMI filters.

Figure 30. Drivers With Slew Rate Control

Figure 31. EMI Measurements CISPR 25 Class 5, Without Slew Rate Control

Figure 32. EMI Measurements CISPR 25 Class 5, With Slew Rate Control

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