SWCS142 July 2018 TPS650861
PRODUCTION DATA.
When a valid power supply is detected at the VSYS pin as VSYS crosses above VSYS_UVLO_5V + VSYS_UVLO+5V_HYS, the power-up sequence is initiated by driving one of the control input pins high, followed by the rest of pins in order. Figure 5-10 is an example where CTL1–CTL4 are defined to control four groups of VRs, while GPO3 and GPO4 are defined to provide a PGOOD status of two groups. The control input pins do not necessarily have to be pulled up in a staggered manner. For instance, if CTL2 is pulled up from the preceding group of VRs before PGOOD has been asserted at GPO1, the BUCK4 enable will be delayed until the PGOOD is asserted.