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TIDA-01021: LMX2594 Power Supply

Part Number: TIDA-01021
Other Parts Discussed in Thread: LMX2594, TPS7A8300,


I am trying to understand the way LMX2594 are powered.

I can see there are several options, I guess one of which is using +3.3V_ALL that is supplied by TPS54318RTE.

However I am more interested in supplying 3.3V using the LDOs.

The LMX2594 is powered by U12 (TPS7A8300). The input to U12 is either 5VIN or +3.3V_ALL. I guess supplying 5VIN would cause roo much heat generated in the LDO while if you apply +3.3V_ALL to U12 at the output you would not get 3.3V.

So I guess for using the LDOs TPS54318RTE  is configured to produce a liittler more than 3.3V? Am I right?

Shortly what I am trying to learn is the chain of supplies powering the LMX2594 a sequential order and the corresponding voltages at the output of each stage?


  • Hi Mike,

    TIDA-01021 schematic shows various option for powering up the multiple devices.

    During the testing various options were tried and the best option was identified the powering up LMX2594 and +3.3V_VCO using the LDOs (U12 & U11 respectively) for better phase noise performance at high frequency clocks. whereas other supplies are generating using the TPS54318RTE. 

    so here, 5VIN is applied to U12 and U11 for generating the +3.3V_LMX/+3.3V_LMXRF and +3.3V_VCO respectively. Schematic should be updated as follows: Remove L24, L26, L29, & L19 and insert L33, L25, L27 & L21.

    Since LMX2594 doesn't need any power sequencing and hence we don't have powering sequencing in this design.

    Best Regards,
    Ajeet Pal