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TLV3201: Propagation delay is not matching with datasheet parameters.

Part Number: TLV3201

Hello,

The datasheet propagation delay parameter is not matching with the simulation for sine input.

The delay with the sine input is 996ns which is not matching with the datasheet.

I have checked the same simulation with PWM input and the results are matching with the datasheet parameters. Please provide the input parameters for the sine inputs and the reason why it is not matching.

Thanks and Regards

Ashish Nawani

  • Hi Ashish,

    the propagation delay times are specified for input overdrive voltages of 20mV and 100mV. But in your application the input overdrive voltage is only 138µV:

    ashish_tlv3201.TSC

    This is the reason why the propagation delay time is about 1.3µs:

    Kai

  • Ashish thanks for your post and as usual, thanks Kai for your insightful comments.

    As Kai noted, the propagation delay for comparators does vary with the level of overdrive (the voltage level the input waveform reaches above the threshold).  However, I need to check if this is modeled in the TLV3201.  Someone will get back to you by tomorrow after we review the model.

    Chuck

  • Hi Ashish,

    We do not model the propagation delay's variation with input overdrive as we just model the typical datasheet value regardless of overdrive amount. In this case, we took the worst case amount of 47 ns.

    Are you using our most updated model? It is named "TLV3201 PSpice Model" in the web product folder. I have also attached it. 

    Thank you for bringing this to our attention!

    Chi

    sbombt6 (1).zip

  • Hello Nguyen,

    I tried simulation with the attached model, for input sine wave: Delay increased to nearly 8 times compared with the previous model (01JUN2012). Please find the simulation result attached.

    With PWM input delay remains the same.

    Please provide overdrive vs delay graph/table/data so that the simulation and calculated parameters can be equated/matched.

    Thanks and Regards

    Ashish Nawani

  • Hello Chuck,

    Please let me know of any updates.

    Thanks and Regards

    Ashish Nawani

  • Hi Ashish,

    with a so slowly varying input signal and so little overdrive you cannot expect a propagation delay of way less than 1µs here. This is entirely unrealistic. Keep in mind that the period of 20Hz sine is 50ms. 1µs is 1/50000 of the 20Hz period! Even the least real world noise will make the skip moment jitter by way more than 1µs.

    Kai

  • Ashish,

    There is a prop delay vs input overdrive graph (Figure 19) in the datasheet but as Kai mentioned, your input signal is so slow that you're going to be getting inaccuracies  in the prop delay. 

    Thanks Kai for your input.

    Chi