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The parameter of TPS5440A in datasheet

takahiko yokota
Mastermind 7135 points
Other Parts Discussed in Thread: TPS54140

Hi

I design circuit TPS54140.

I calculated Gmod(fc) by the value of datasheet, but the calculated result differed it of datasheet.

Could you tell me value of, fz(mod), ge(ea), fp(mod), gm(ps)、RLOAD、fc、fp(mod), Cout and RESR in datasheet?

Best regards,

Yokota

  • 0
    TI__Guru**** 191445 points

    Those are al given in the datasheet:

    Fz(mod) is given in eq 42.  It is the ESR zero of the output capacitor.

    ge(ea) SP? (I suppose you mean gm(ea) ) is specified in the electrical characteristic table page 5.  gm(ea) = 97 uMho.  It is the transcunductance of the error amplifier.

    Fp(mod) is given in eq 41.  It is the ideal pole of the output filter.  This assumes ideal current mode with no slope compensation.

    Gm(ps) is  is specified in the electrical characteristic table page 5.  gm(ps) = 6 A/V.  It is the transcunductance of the power stage. 

    RLOAD is the load resistance or Vout / Iout.  The user provides those values.

    Fc is the crossover frequency.  It is usually termed as Fco.  The user defines it, but it is bound by the equations 43, 44, 45 and 46.

    Cout  is the output capacitance,  the user provides that value.  You can choose it based on section 9.2.2.3 of the datasheet.

    RESR is the effective series resistance of the output capacitor.  You will get that from the datasheet of the output capacitor you choose.  The maximum value you can use is determined by eq 36.