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peak detector : CS0951017

  • Hello rocco, 

    I am not able to access the CSC link you provided.  Please provide a description of the question you would like answered. 

    Thank you,  


  • Number: CS0951017
    Contact: rocco pochy
    First name: rocco
    Last name: pochy
    Short description: peak detector
    Phone: 15104380500
    Company: Lighthouse Worldwide solutions
    Company phone:
    Language: English
    State: Open
    Provide case details or comments:


    I am creating a peak detector circuit to capture pulses from 1-50us with a pulse height range from 5mV to 4V.  I have put simulated the issue with the circuit that outputs the peak height with a gain of 2X. Based on the design, I am not sure where this is coming from. I have included a TINA file that simulates the issue. I am looking for ideas or suggestions.


  • Hi Rocco,

    you could do it this way:


    Or this way:



  • Can you explain why the initial design has the gain issue?

  • Hi Rocco,

    not all OPAmps are equally well suited in a peak detector circuit. The OPA1678 is instable in this circuit, oscillates during the rising edge and is wildly overshooting. The following simulation shows the best performance that I could achieve with the OPA1678. But still instability can clearly be seen:


    The THS4631 and OPA356 are better suited here.


  • Since I am look at a low cost application. What op amp parameters do I need to address to avoid the oscillations in the circuit?  Ideally I am looking for a quad package. The suggested op amp are too expensive for the application.

  • Hi Rocco,

    the OPA2301 could be used and the OPA2356.


  • What is it about the chips you choose that makes them good for this circuit?

  • Hello Rocco,

    If you are interested in a quad package high speed op-amp, the most cost effective web price suggests the TLV3544.  You can compare the datasheet values for noise, output swing, power supply, and other requirements and see how it differs from Kai's recommendations.  I am not sure what your price target is; once you have an idea of your maximum cost you are willing to pay for a solution, you can investigate TI parts which are nearer to that value.

    Kai's recommendations, all four of them, are well-suited to your application and are stable.  You will want to observe the stability of your circuit and be aware of oscillations and overshoot depending on the amplifier you select.  The higher the necessary performance with respect to noise, bandwidth, gain, output swing, and power consumption, the more expensive a product is likely to be.  Without knowing more system details, it is difficult for us to find you a recommendation.  

    If you should need assistance in simulating various op-amps, I can help once I know more about your budget and performance concerns.   



  • Thanks for you input.  I was hoping to get a sub-$1 component (qty +500) with a bandwidth around 20MHz, +/-5VDC supply, low noise, in a 14-TSSOP package. I am dealing with pulses that are from 1 to 50 usec over a voltage range of 5mV to 4.5V.

    I would in interested in trying the TLV3544. How do I import the SPICE model into TINA? I also note the TLV9064.

    Is there something particular two the suggested op amps that I should look for in refining my selection that will assure it is stable in the circuit I have provided?

  • Hi Rocco,

    the TLV9064 is way too slow and it is instable:


    The OPAmp should have a bandwidth of at least 200MHz in combination with a sufficiently high slew rate. The OPA356, OPA2356 and THS4631 fullfill this condition. But the TLV9062 has a bandwidth of only 10MHz.

    The TLV3544 recommended by Alec can also be used with a slight quality loss for low input voltage steps:



    I would in interested in trying the TLV3544. How do I import the SPICE model into TINA?

    Best you open the

    TLV354x TINA-TI Reference Design (Rev. A)

    and copy and paste the OPAmp into the orginal simulation.


  • Hello Rocco,

    Kai is correct; it is always fastest & easiest to use the existing TINA-TI Reference Design instead of manually importing and setting up a standalone SPICE model for a part.

    Thank you for providing additional information.  Kai is also correct in the assessment of the TLV3544 in TINA-TI; you are encouraged to model and simulate the device to determine if the tradeoffs compared to the devices recommended earlier in the thread are important to your application.