Many of the common power supply sequencing methods can be implemented using the Soft Start - Tracking, INHIBIT and POWERGOOD pins. The sequential method is illustrated using two LMZ31506 devices in the top image shown here. The POWERGOOD pin of the first device is coupled to the INHIBIT pin of the second device which enables the second power supply once the primary supply reaches regulation. The graph in the top right corner shows sequential turn-on waveforms of two LMZ31506 devices. Simultaneous power supply sequencing can be implemented by connecting the resistor network of R1 and R2 shown in the bottom left figure to the output of the power supply that needs to be tracked or to another voltage reference source. The figure in the bottom right corner shows simultaneous turn-on waveforms of two LMZ31506 devices.