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TLV4316: Output spike issue

Part Number: TLV4316
Other Parts Discussed in Thread: TLV316, TLV2772, TLV9064, OPA2316

Hi  Experts:

I found there is a spike issue when power on the TLV4316 , the detail is :

It is a summator topology like below used to be the Over current detection for the Motor driver system .

Question: Could you please explain the spike and how to resolve it?

BTW, even we disconnect the load (remove the R58) , the spike is also existed.

Thanks!

The below waveform show Output vs the 3.3V pin, you can see the spike come out when the VCC go above 1.8V.

The waveform below is the output vs the Vin+ input , there is no signal input during the power on

  • Hello Jason,

    TLV316 opamp circuit topology is such that it does not hold the output of the op-amp close to gnd until all the bias circuit is up and running when the power supply is ramping up slowly. That is why there is a jump. 

    One solution to this problem is you can load the output of the op-amp with a 1K ohm resistor. That will reduce the amplitude of the spike.

    Another solution is to use the TLV316 with shutdown feature and delay the enabling of the part until the supply voltage reaches 1.8V. 

    Please let me know if this solves your problem.

    Regards,

    Sanjeev

  • Hi  Sanjeev:

    Thanks for your reply.

    Why does the TLV2772 has no issue , because of the different output structure ?

    For the solution 1, do you mean the 1kohm pull down resistor on the output ? 

    For the solution 2, i didn't find theTLV316 has the shutdown feature.

  • Hi Jason,

    I have a better solution than what I provided in my previous reply. TLV9064 does not have startup spike problem. I just confirmed it in the lab. It is 10 MHz opamp just like TLV4316 and has some specification even better that TLV4316. It is a pin-to-pin compatible part with TLV4316. 

    The answers to your question  

    I am not familiar with the topology in TLV2772 but it could be different than in TLV4316 and hence is immune to start-up spike. 

    Solution 1: Yes, 1k ohm pull-down resistor on the output.

    Solution 2: I meant to say OPA2316 https://www.ti.com/store/ti/en/p/product/?p=OPA2316SIDGSR

    I hope I resolved your problem.

    Sanjeev