Several features are included to simplify compliance with CISPR 25 and automotive EMI requirements. To reduce input capacitor ripple current and EMI filter size, the device can be configured to operate in a stack of either two, four, or six phases with corresponding phase shift interleave operation based on the number of phases. For example, in a 4-phase setup, a 90° out-of-phase clock output setup works well for cascaded, multi-channel, or multi-phase power stages. Resistor-adjustable switching frequency as high as 2.2 MHz can be synchronized to an external clock source to eliminate beat frequencies in noise-sensitive applications. Optional spread spectrum modulation further improves the EMI signature.

The CONFIG terminal is used to set up the device for either dual output or single output multi-phase operation. The spread spectrum can also be turned on and off with different resistor values.

When configured in single output multi-phase operation, the VOSNS2 pin becomes the output of the error amplifier (COMP) and a resistor and capacitor are needed at this pin to compensate the control loop. R_C = 11 kOhms, C_C = 2.2 nF can be used in initial evaluation for many designs. Increasing the resistance results in higher loop gain and tends to require proportionately larger output capacitors. Decreasing the capacitance increases the loop response of the device, resulting in faster transients but can lower phase margin at the cross-over frequency and can require adjustments to the output capacitance. The table below has several settings for different output configurations.