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:

1. Step down using high-efficiency switching converters, followed by a second stage of regulation to provide switching noise reduction and improved voltage accuracy.
2. Directly step down the final ADC supply voltage using high-efficiency switching converters. This approach provides the best efficiency, but care must be taken to ensure switching noise is minimized to prevent degraded ADC performance.

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 the TPS62085, TPS82130, TPS62130A, and similar devices.

Recommended Low Drop-Out (LDO) linear regulators include the TPS7A7200, TPS74401, and similar devices.

For the switcher only approach, the ripple filter must be designed with a notch frequency that aligns with the switching ripple frequency of the DC-DC converter. 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. Figure 192 and Figure 193 illustrate the two approaches.

NOTE:

FB = ferrite bead filter.

Figure 192. LDO Linear Regulator Approach Example

NOTE:

Ripple filter notch frequency to match the fs of the buck converter.

NOTE:

FB = ferrite bead filter.

Figure 193. Switcher-Only Approach Example