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TLV1841: Propagation delay of datasheet and Spice Model comment does not match simulation

fpgr
Prodigy 30 points
Part Number: TLV1841

Tool/software:

Hi all!

I did a simulation using the Spice model of TLV1841 in an application where "reaction time", i.e. propagation delay is critical.

  • The datasheet specifies a tpd of about 65ns for a supply voltage of 12V and an input overdrive of 100mV.
  • A comment in the spice model says: "Propagation Delay (typical 75ns)"

In my simulation I did a ramp on the input and measured the propagation delay for a 100mV overdrive (see picture attached). I get a tpd of more than 350ns which is way more than suggested by the datasheet and the spice model notes. 

Any ideas?

P.S.: in the screenshot you see the green line which is the difference voltage on the comparator inputs, i.e. (Vin+ - Vin-), the left cursor is at a difference voltaeg of 100mV (100mV overdrive) , the right cursor is at the point where the output (red line) starts to react. Seems like I get ~320ns propagation delay) 

  • +1
    TI__Genius 11505 points

    Hi fpgr,

    The PSpice model for the TLV1841 seems to have a couple of errors (see how the .lib defines VCCI and VCCO in the top level subcircuit when those pins do not exist in the real device). Along with those errors, it seems like the typical propagation delay is also incorrect there.

    I looked in the TINA model for the TLV1841, and that seems to have the correct propagation delay in that model.

    Please try your simulation by importing this .lib:

    tlv1841_tinalib.lib

    I'll make a note of the error you found and work on getting a corrected model up on the web sometime in the future.

  • 0 in reply to HO SIU
    Prodigy 30 points

    Indeed, I first wondered about the additional pins, but then saw that the TLV187x has a split supply scheme and I found it reasonable that the spice model for the TLV1841 was derived from latter. Anyway - your TINA model shows better conformance - thanks!