9.3.9 Power-Up Sequence

Figure 50 shows the steps to power up the device.

Figure 50. Simplified Power-Up Sequence

The first step is to apply all the supplies needed for device to be functional. The RESETn should be kept at logic 0 when power supplies start ramping. LMK046xx devices do not need any specific power up sequencing for the external power supplies. The on-chip POR logic makes sure that the device stays in power-down state until all the supplies are available.

After all the device power supplies are stable, RESETn can be released to logic 1. The device enters idle state and is now ready for the SPI programming.

After programming the device configuration, the DEV_start-up should be triggered using SPI, which initiates the device bootup sequence. The loading of the configurations to the corresponding functional blocks and enable sequencing is cared for by the on-chip state machines. One-time SYNC is also issued to the output channels during device booting. The lock signals for the PLLs can be observed at the STAT0/1.

Figure 51 shows the LMK0461x booting sequence of operations in details. Branch A, B, and C run in parallel.

Figure 51. Detailed Power-Up Sequence