SBAS688E April 2015 – September 2017 AFE5816
The device requires a total of five supplies in order to operate properly. These supplies are: AVDD_3P15, AVDD_1P9, AVDD_1P8, DVDD_1P8, and DVDD_1P2. See the Recommended Operating Conditions table for detailed information regarding the minimum and maximum operating voltage specifications of different supplies.
Figure 106 shows the suggested power-up sequencing and reset timing for the device. Note that the DVDD_1P2 supply must rise before the AVDD_1P8 supply. If the AVDD_1P8 supply rises before the DVDD_1P2 supply, the AVDD_1P8 supply current is several times larger than the normal current until the DVDD_1P2 supply reaches a 1.2-V level.
100 µs or later after the start of clock, write the PLLRST1 and PLLRST2 bits to 1. Then, after waiting for at least 10 µs, write both these bits to 0, which helps initialize the PLL in a proper manner. This method of PLL initialization is also required whenever the device comes out of a global power-down mode or when ADC_CLK is switched off and turned on again.