Can anyone recommend an integrator op amp?

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Discussion Overview

The discussion centers around the selection of an operational amplifier (op-amp) for building an integrator circuit that can handle 15 volt, 65 nanosecond pulses at a repetition rate of 100 kHz, with a desired time constant of 20 microseconds. Participants explore the requirements for low input bias current and sufficient bandwidth for the application.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant, Paul, specifies the need for an op-amp that can integrate 65 ns pulses and emphasizes low input bias current to minimize DC drift.
  • Another participant questions the feasibility of any op-amp responding to 65 ns pulses and asks for more details about the intended application.
  • Paul clarifies that the input pulse is Gaussian in shape, approximating to half a sine wave, and calculates a frequency of 7.69 MHz, suggesting that a suitable op-amp should be available with the required bandwidth and low input current.
  • A participant suggests that a standard op-amp might suffice and mentions the TLC27M2AID, which has a 1 pA input bias current and an 800 MHz bandwidth.
  • Another participant recommends looking for a Texas Instruments (TI) op-amp with a high gain bandwidth product (GBW).

Areas of Agreement / Disagreement

There is no consensus on the suitability of op-amps for the specified application, with some participants expressing skepticism about the ability of any op-amp to respond to the fast pulse duration while others suggest potential options.

Contextual Notes

Participants have not agreed on the specific requirements for input bias current or bandwidth, and there are unresolved questions about the practical implementation of the integrator circuit with the specified pulse characteristics.

Who May Find This Useful

Electronics engineers, hobbyists working on signal processing applications, and those interested in operational amplifier selection for high-speed applications may find this discussion relevant.

ElecTec
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Hi,

I'm building an integrator using an op-amp to integrate 15 volt 65nS pulses at a repetition rate of 100Khz using a 20uS time constant.

Can anyone recommend a suitable op-amp for this application. It needs to have very low input bias current to minimise d.c. drift and have sufficient bandwidth. The cost is not important but it needs to be readily available.

Many Thanks.

Paul.
 
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No opamp is going to respond to 65ns pulses. Can you say more about what you are trying to do? We may still be able to suggest some ways to accomplish what you want.
 
Hi,

Thanks for replying to my query.

The input pulse is gaussian in shape and 65nS wide. Taking this as approximating to half a sine wave I calculated the periodic time to be 130nS. This is a frequency of 7.69Mhz and I thought I would be able to get a suitable op amp with that bandwidth and low input current.

Any suggestions?

Regards,

Paul.
 
how low input bias, is pA standard? just use a regular op amp should work
do a search at digikey compare.
TLC27M2AID has 1pA input bias current, bandwidth 800MHz
 
Look for something on TI that has a high GBW (gain bandwidth product)
 

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