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TLVH431: simulation model pulse response doesn't agree with datasheet specification

ZM
Prodigy 220 points
Part Number: TLVH431
Other Parts Discussed in Thread: TLV431, TL431LI

Hello, 

I am using the TLVH431 simulation model in LTspice to evaluate the pulse response specified in datasheet, fig 12 and 13 on page 11 and 12. Despite I use the same circuit as in datasheet, the result is far from datasheet waveform. The reference voltage has large oscillation upon power up. When the rising time of the 3V input is 200ns, the reference oscillates between 3V and 0V. The oscillation dies down after 1.7us. When the rising time is slowed to 600ns, the reference still has some oscillation with larger amplitude and longer duration than the datasheet waveform. 

I will trust datasheet over the simulation model for now until I can verify it on a sample. Meanwhile please update the pspice simulation model. Thanks.

Best regards,

Zhenyu

  • 0
    TI__Mastermind 19370 points

    Hi Zhenyu,

    I performed this test on the bench and it matched the datasheet. You can proceed with confidence that the datasheet matches the samples.

    -Marcoo

  • 0 in reply to Marcoo Z
    Prodigy 220 points

    Hi Marcoo,

    Thank you for your confirmation. So far TLVH431 is the only voltage reference with fast enough power up speed that I can find. If you know any other voltage reference that can be fully functional within 300ns upon power up, feel free to let me know.  

    Best regards,

    Zhenyu

  • 0 in reply to ZM
    TI__Mastermind 19370 points

    Hi Zhenyu,

    I would say to look into the TL431LI. From my testing, It was functional at 300ns with regulation at 600us with no output cap. The TLV431 took a little bit longer to regulate.

    Can you tell me more about your application? Why do you need such a fast start up?

    -Marcoo

  • 0 in reply to Marcoo Z
    Prodigy 220 points

    Hi Marcoo,

    In the application upon power up the circuit needs to determine the system status and react accordingly within a short time window. A fast reference voltage is essential for the circuit to make correct judgement right after power up. 

    Thanks,

    Zhenyu