JAJSEY1 April 2019 ADC12DJ5200RF
ADVANCE INFORMATION for pre-production products; subject to change without notice.
The device requires two different power-supply voltages. 1.9-V DC is required for the VA19 power bus and 1.1-V DC is required for the VA11 and VD11 power buses.
The power-supply voltages must be low noise and provide the needed current to achieve rated device performance.
There are two recommended power supply architectures:
TI WEBENCH® Power Designer can be used to select and design the individual power supply elements needed: see the WEBENCH® Power Designer
Recommended switching regulators for the first stage include LMS3635-Q1, LMS3655-Q1, TPSM84424 and similar devices.
Recommended low drop-out (LDO), low-noise linear regulators include the TPS7A84, TPS7A83A, TPS7A47 and similar devices.
For the switcher only approach, the ripple filter must be designed to provide sufficient filtering at the switching frequency of the DC-DC converter and harmonics of the switching frequency. Make a note of the switching frequency reported from WEBENCH® and design the EMI filter and capacitor combination to have the notch frequency centered as needed. Each application will have different tolerances for noise on the supply voltage so strict ripple requirements are not provided. Figure 127 and Figure 128 illustrate the two approaches.
NOTE:
FB = ferrite bead filter.NOTE:
Ripple filter notch frequency to match the fs of the buck converter.NOTE:
FB = ferrite bead filter.