TPS38-Q1: About PSpice Model

Hi MIchael,

Thank you for your question. Is this simulated using PSpiceforTI or independent ORCAD? Also what version are they using?

Jesse 

Hi Jesse,

Here is what you requested

* ORCAD (Ver 17.4)

Pls check it and let me know.

Thanks & Best regards,

Michael

Hi Jesse,

I have recommended to my customer to use PSPICE-FOR-TI.

So they agreed.

Here is additional questions from our customer.

They have a plan to use TPS38A010122DSKRQ1.

Could you please give me answer about each item after review?

1. How do I set for Part Properties for PSPICE Model?

    I need to set the Pspice Model Property, and could you check whether the settings below are correct or not for TPS38A010122DSKRQ1?

    What does it means "1" or "0" for CH1_INPUT or CH2_INPUT?

    * Setting

      CH1_INPUT = 1, CH1_OUTPUT = 0, CH2_INPUT = 1, CH2_OUTPUT = 0, HYS1 = 0.02, HYS2 = 0.02, VTH1 = 0.8, VTH2 = 0.8

2. Do I have to write 0.02 in HYS1, HYS2 if hysteresis is 2%?

    Is it right?

3. When I set like below, Simulation results confirm that the RESET2 output is affected by the SENSE1 voltage level.

    In case, how does this symptom happen? could you check whether the error is caused by a missing part in the model properties.

    * Setting

      CH1_INPUT = 1, CH1_OUTPUT = 0, CH2_INPUT = 1, CH2_OUTPUT = 0, HYS1 = 0.02, HYS2 = 0.02, VTH1 = 0.8, VTH2 = 0.8

    * Test

4. About Hysteresis Voltage Level.

As shown in the Timing picture below, when a 3.3V constant voltage is applied to VDD, RESET#1 and RESET#2 signals are output according to the V2 voltage hysteresis level (14.5V / 13.25V).

As shown in the Pspice for TI circuit diagram below, we want to set the hysteresis level 1.25V (14.5V-13.25V=1.25V) to suit the user definition using NMOS.

When configuring the circuit, it was confirmed that hysteresis operation is possible, but a different hysteresis level than intended occurs.

Therefore, we request a hysteresis circuit suitable for user definition recommended by TI and calculation data for the resistance (R1, R5 below) suitable for the corresponding hysteresis level.

(Considering the hysteresis 2% Tol, R1 & R5 were adjusted, but a different hysteresis level than intended was confirmed, and RESET#2 intentionally delayed it.)

Best regards,

Michael

Hi Jesse,

Thanks for your feedback.

I need your reply to each question on my above thread for our customer and me.

I don't understand about your comment that "The device parameter for this model is already preset for the TPS38A010122"

When I checked the library parameter of TPS38-Q1 PSpice Model, this is different from TPS38A010122.

Do I misunderstanding?

We need more your kind explanation.

Best regards,

Michael