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AWR1243: LdoBypass mode

Tim Li
Prodigy 190 points
Part Number: AWR1243


Hello，

We are trying to design our own board using AWR1243.  I wonder if we can provide the RF module with 1.0 volt instead of 

1.3 volt with Ldobypass mode disable, will it affect the RF front end?

Regards!

TIme

  • 0
    TI__Guru**** 150224 points
    Hi, is this a single AWr1243 board or a multiple AWR1243 board?

    thank you
    Cesar
  • 0 in reply to Cesar
    Prodigy 190 points
    Thank you for your reply,
    it would be a multiple AWR1243 board.

    Tim
  • 0 in reply to Tim Li
    TI__Mastermind 18500 points
    Hi Tim,

    LDO bypass mode is supported in the AWR1243 ICD, specifically for this purpose. See ICD Section 5.11.6 "Sub block 0x02CC – AWR_RF_LDO_BYPASS_SB" for details.

    But yes, ADC IF specturm is very sensitive to noise on the RF1 and RF2 supplies. With the internal LDO bypassed the down-stream components do not receive the PSRR benefit provided by the internal LDO. So this low-noise requirement is passed on to the PCB level. Please see the AWR1243 datasheet, table 5-2 "Ripple Specification" for the details. www.ti.com/.../awr1243.pdf

    This has been setup on soon to be released TI single AWR1243 evaluation boards and is also the mode of operation on our upcoming quad-AWR1243 cascaded radar board. But these use specific PMIC buck-converters in combination with passive LC filters to notch out switching noise that appear in the ADC IF spectrum. However, I do not have reference schematics to share publicly yet.

    Please let me know if that answers all of your questions on these topics.

    Thank you,
    Randy