DLPS037H October 2014 – June 2024 DLPC900
PRODUCTION DATA
Although the DLPC900 requires an array of power supply voltages, for example, 1.15V, 1.8V, and 3.3V, there are no restrictions regarding the relative order of power supply sequencing to avoid damaging the DLPC900, as long as the system is held in reset during power supply sequencing. This is true for both power-up (reset controlled by POSENSE) and power-down (reset controlled by PWRGOOD) scenarios. Similarly, there is no minimum time between powering-up or powering-down the different supplies feeding the DLPC900. However, power-sequencing requirements are common for the devices that share the supplies with the DLPC900.
Power-sequencing recommendations to ensure proper operation are:
It is assumed that all DLPC900 power-up sequencing
is handled by external hardware. It is also assumed that an external power monitor will hold
the DLPC900 in system reset during power-up (that is, POSENSE = 0). During this time, all
controller I/Os are tristated. The primary PLL (PLLM1) will be released from reset upon the
low-to-high transition of POSENSE, but the DLPC900 will be kept in reset for an additional
60ms to allow the PLL to lock and stabilize its outputs. After this delay the DLPC900
internal resets will be deasserted, thus causing the processor to begin its boot-up
routine.
Figure 8-2 shows the recommended DLPC900 system power-up sequence of the regulators: