The device has a spread spectrum clocking function that can reduce electromagnetic interference (EMI). When the SSC function is active, the device modulates the switching frequency to approximately ±10% the nominal value. The frequency modulation has a triangular characteristic (see Figure 8-11).

To use the SSC function, make sure that:

• SSCEN = 1 in the CONTROL1 register.
• The device is not synchronized to an external clock.

TI recommends to use FPWM operation when using SSC, but SSC is available with PSM operation. To disable the SSC function, make sure that SCCEN = 0 in the CONTROL1 register.

To use the SSC function with multiple devices in a stacked configuration, make sure that the primary converter runs from the internal oscillator and synchronize all secondary converters to the primary clock (see Figure 8-14).