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IWR6843: switching frequency of supply

David Park
Expert 6710 points
Part Number: IWR6843

Hi,

Customer would like to adopt discrete DCDC for 3.3V, 1.8V, 1.2V, 1.0V instead of PMIC due to leadtime issue.

Can lower switching frequency DCDC than 4MHz be used for it?

Thanks.

  • 0
    Intellectual 430 points

    Is there official discreted DCDC solution available for 6843 application?

  • 0 in reply to Hui Chen
    TI__Genius 16640 points

    Hello.

    Thank you for reaching out to Texas Instruments. We are working on your inquiry, please allow anther day for us to get back to you. 

    Thanks,

    -Shareef

  • 0 in reply to E. Shareef
    TI__Genius 16640 points

    Im going to loop in Chethan from our team to respond to your query, He has experience working with PMIC.

    -Shareef

  • 0 in reply to E. Shareef
    TI__Mastermind 25835 points

    Hello Hui Chen,

        You could refer to below IWR6843 LEVM this uses discrete DCDC solution. 

    Not all the discrete DCDC solutions would be applicable, In this reference design many factors such as 1) Higher switching frequency 2) Ripple/Noise 3) Load transient performance 4) Forced PWM 5) Spread spectrum clocking 6) Post DCDC filters etc are co-designed along with mmWave sensor.

    https://www.ti.com/tool/IWR6843LEVM

    You could use below reference schematics:  

    https://www.ti.com/lit/zip/swrr178

    In the reference schematic fixed output voltage parts are used, If the fixed output voltage parts are not available, then Variable output part could be used with external resistors to select right voltage. 

    Thanks and regards,

    CHETHAN KUMAR Y.B. 

  • 0 in reply to CHETHAN KUMAR Y.B.
    Intellectual 430 points

    Hi Chethan

    Thank you for your reply.

    I downloaded the materials of iwr6843 LEVM for research. Unfortunately, due to the impact of the COVID-19, many of TI's devices could not be purchased. I searched DigiKey and Arrow for the power chips used in this EVM, and all of them were out of store.

     

    We agree with the description in the following paragraph completely. We have the ability to design circuits independently, but because the datasheet and design guide of TI's radar chip lacks the indicators of these key factors mentioned below, we can't determine which power supply schemes are available. Even if we test the board after product, we can't judge whether the power solution meets the demand. So we have to follow the TI EVM solution closely.For example, what is the minimum switching frequency? Ripple noise tolerance? The min requirements of power dynamic response? And so on. 

    ----

    " Not all the discrete DCDC solutions would be applicable, In this reference design many factors such as 1) Higher switching frequency 2) Ripple/Noise 3) Load transient performance 4) Forced PWM 5) Spread spectrum clocking 6) Post DCDC filters etc are co-designed along with mmWave sensor.”

    ----

    I think a specific and detailed design example is secondary, especially in the case of serious stock shortage. Clear design constraint requirements and design criteria are the most critical. With these, customers can carry out completely independent design without ti's EVM. This can really solve the problem of component shortage.

     

    Regards

    Chenhui

  • 0 in reply to Hui Chen
    TI__Mastermind 25835 points

    Hello Chehui,

        Your points are valid, Currently most of the semiconductors manufacturer are going through the supply shortage situation, this includes PMIC and DCDC converters as well. 

    Do you have local sales or Field team contact? We could check If the devices availability to support your development. 

    Thanks and regards,

    CHETHAN KUMAR Y.B.