Preliminary Technical Data
UG-1828
Rev. PrC | Page 283 of 338
LDO CONFIGURATIONS
Note: Consider this section carefully. Failure to implement the LDO modes correctly may result in an incorrect voltage being applied and
potentially damage RF circuits.
VDDA_1p0 is a power domain that powers all the Tx and Rx LO circuits. This domain can be powered using internal LDOs that generate
the 1V needed from the 1.3V supply. Alternatively it can be powered externally, bypassing some of internal LDOs. This can be used in
cases where the customer wants power savings or already has a 1v supply in the system. Some power savings can be achieved by turning
off the LDOs and applying a higher efficiency external power source to the 1V rails. The new 1V external power domain will need to be a
low noise supply with a tolerance of ±2.5%.
The LDO configurations on the ADRV9001 can affect the overall power consumption. On the ADRV9001 evaluation board all the
internal LDOs are used and they generate the 1v needed for all the rails. This allows for different RF channels to be used while evaluating.
In a end system the user will know what RF channels they are using and can tailor the RF channels to the system. Three examples of this
can be seen in Figure 266.
To implement an ideal LDO configuration for the end use case, the user will need to:
•
Use the application to determine how many Tx, Rx and LO channels are needed
•
Design a power supply to implement the determined use case
•
Choose what LDO configuration is needed and set the LDO modes appropriately
APPLICATION POWER NEEDS
Deciding what LDOs to use/bypass will depend on the Tx, Rx and LO combinations that are going to be used. For example, in 1T/2R
FDD use case the user will not use one of the transmit channels and should then also power down the internal LDOs for this channel.
Details on how to wire the powers domains can be found in the Power Supply Configuration section above.
The following board power supply configurations are supported: