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TLV62090 GainPhase

KIYOSHI NARISAWA1
Expert 1510 points
Other Parts Discussed in Thread: TLV62090, TPS62080

Dear TI

I measured the phase margin at below condition on web EVM and showed the result as below.

Vin=5V,Vo=3.3V,Io=1A ,Cout=22uF    Rs=51ohm, Signal=3mVp-p

 Is the result correct? or is anything wrong?

If you have any referece data, please let me know and send below address.

address: narisawa-k@clv.macnica.co.jp 

 Thank you and best regards

K.Narisawa

 

  • 0
    TI__Expert 5055 points

    Hi,

    Could you please describe how you measured the loop?

    This app note gives guidance how to Measure the Control Loop of DCS-Control™ Devices

    http://www.ti.com/lit/an/slva465a/slva465a.pdf

    Regards,

    Michael

  • 0 in reply to Michael Helmlinger
    Expert 1510 points

    Hi Michael-san,

    I measured PM data by using the web orderable EVM.

    Below figure is recommended schematic.VOS is connected after Rs on loop.

     

    But I measured it on below schematicthe of web orderable EVM.

    VOS is connected before Rs.

    VOS is connected with output directy, therefore it don't have enough space to put into Rs before VOS pin. 

    Do you have any idea to measure PM on web orderable EVM?

    Thank you and best regards

    K.Narisawa

  • 0 in reply to KIYOSHI NARISAWA1
    TI__Expert 5055 points

    Hi,

    You will have to modify the EVM to add the resistor as described in the app note. 

    Regards,

    Michael

  • 0 in reply to Michael Helmlinger
    Expert 1510 points

    Hi Michael-san,

    I measured PM with modified EVM in according to app note.

    The result is as below.Could you please review for that?

     

      22uF waveform is little different for 22uF over.　Is it correct?

    And 22uF over are also correct too? 

    TLV62090 has no product of capacitor on datasheet and also user's guide.

    However TPS62080 has a discription for low ESR capacitor with product. 

    TLV62090 doesn't need low ESR type in ceramic capacitor? 

    Thank you for your kindness.

    Bst Regards

    K.Narisawa

     

     

  • 0 in reply to KIYOSHI NARISAWA1
    TI__Expert 5055 points

    Hi Kiyoshi-san,

    Your results looking very good. With a higher value of Cout, the crossover frequency goes down.

    The TLV62090 also needs low ESR ceramic capacitors. 

    I would recommend at least 2x22uF Cout for 3.3Vout. (DS page 14)

    Best Regards,

    Michael