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TL3474: Pulse Response of PSpice simulation

Part Number: TL3474
Other Parts Discussed in Thread: OPA4172, OPA4131, OPA4132

Dear Specialists,

My customer is simulating TL3474 and has a question.

I would be grateful if you could advise.

---

When I simulated the pulse response with the P-Spice model of TL 3474, although the specified slew rate of TL 3474 is 10 V / us, it is only about 1.6 V / us.

I'd like to know the reason why, simulation model or something.

Simulation model was obtained from TI's WEB, could you please see below.

---

I appreciate your great help in advance.

Best regards,

Shinichi

sloj171.txt
* TL3474 OPERATIONAL AMPLIFIER "MACROMODEL" SUBCIRCUIT

* connections:   non-inverting input
*                | inverting input
*                | | positive power supply
*                | | | negative power supply
*                | | | | output
*                | | | | |
.subckt TL3474-X   1 2 3 4 5
*
  c1   11 12 4.5496E-12
  c2    6  7 25.000E-12
  cee  10 99 9.0000E-12
  dc    5 53 dy
  de   54  5 dy
  dlp  90 91 dx
  dln  92 90 dx
  dp    4  3 dx
  egnd 99  0 poly(2) (3,0) (4,0) 0 .5 .5
  fb    7 99 poly(5) vb vc ve vlp vln 0 6.3662E6 -1E3 1E3 6E6 -6E6
  ga    6  0 11 12 942.48E-6
  gcm   0  6 10 99 9.4248E-9
  iee   3 10 dc 39.194E-6
  hlim 90  0 vlim 1K
  q1   11  2 13 qx1
  q2   12  1 14 qx2
  r2    6  9 100.00E3
  rc1   4 11 1.0610E3
  rc2   4 12 1.0610E3
  re1  13 10 .1
  re2  14 10 .1
  ree  10 99 5.1028E6
  ro1   8  5 50
  ro2   7 99 25
  rp    3  4 109.87E3
  vb    9  0 dc 0
  vc    3 53 dc 1.8066
  ve   54  4 dc 1.8066
  vlim  7  8 dc 0
  vlp  91  0 dc 28
  vln   0 92 dc 28
.model dx D(Is=800.00E-18)
.model dy D(Is=800.00E-18 Rs=1m Cjo=10p)
.model qx1 PNP(Is=800.00E-18 Bf=201.03)
.model qx2 PNP(Is=831.5365E-18 Bf=201.03)
.ends
*$

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                Created  2002, (C) Copyright  2002, Texas Instruments 
                Incorporated, All Rights Reserved

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  • Hi Shinichi-san,

    I agree with what you are seeing. Unfortunately, this model is old (from 2002) and doesn't adequately model all of the non-linear behaviors of the op-amp.

    My recommendation would be to take a look at the OPA4131 or the OPA4172, they both have very similar specs to the TL3474, are newer parts, and have better models to work with.

    Let me know if there is anything else I can assist with.

    Best,
    Paul
  • Hi Paul,

    Thank you for your reply.

    I understand PSpice model of TL3474 is not enough to confirm pulse response.

    I'll share your information to use OPA4131 or OPA4172 instead with my customer.

    I'd like to confirm just in case, is there a plan to improve PSpice model of TL3474?

    I appreciate your great help.

    Best regards,

    Shinichi

  • Hi Shinichi-san,

    Right now there is no immediate plan to update the TLV3474 model but it is something we can look into if the opportunity is right. Please feel free to reach out to me offline if that's something you'd like to discuss.

    Best,
    Paul
  • Hi Paul,

    Thank you for your reply.

    Unfortunately the business is not so big, but it is helpful to update to the latest.
    If you have the other oppotunity, could you please update.

    I appreciate your great help.

    Best regards,
    Shinichi
  • Hi Paul,

    The customer tried OPA4172 simulation and worked well.

    He has an additional question, could you please advise.

    ---
    I confirmed the model of OPA 4172, a valid simulation waveform appeared.
    Thank you for your support.

    Also I have a question, could you please advise.

    OPA4132 is FET input and slew rate is twice(20V/us) that of OPA4172(10V/us), so I think that it is not "very similar specs to the TL3474".

    What are the similarities you mentioned?

    ---

    I appreciate your great help and cooperation.

    Best regards,
    Shinichi
  • Hi Shinichi-san,

    The parts aren't perfect matches and depending on the customer's application, they could choose one device or the other. The OPA4172 is a closer match than the TL3474 if the slew rate is an important specification.

    If you provide a little more information on the customer's application and requirements I can help provide a recommendation for a modern part with a good model.

    -Paul
  • Hi Paul,

    Thank you for your reply.

    I understand your idea.and share this with the customer.

    If he give me  the concept of the amplifier, I consult you again.

    I appreciate your great help.

    Best regards,

    Shinichi