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S-parameter files on your website do not have the noise characteristics attached.

Marvin Cantos
Expert 5675 points
Other Parts Discussed in Thread: TINA-TI, OPA818, OPA855

Hi Team, 

Good day. I am posting this inquiry on behalf of the customer.

For an astronomy project at our university (TU/e, NL), we are looking for a suitable LNA to connect to our antenna.

One of the critical parameters we would like to simulate in Keysight’s ADS is its noise performance.

However, it seems that the S-parameter files on your website do not have the noise characteristics attached.

Is this available somewhere else?

 

Next to that, we are mainly interested in the relatively low-frequency band of 1 to 100 MHz.

Unfortunately, most of your S-parameter files seem to have a rather limited number of frequency points in this band.

Any recommendations for specific amplifiers or methods that solve this issue?”

To add to that, we also aim for an amplifier that is frequency-invariant (i.e. constant frequency response) over the full 1-100 MHz range.

Please help to advise. Thank you for extending your support.

Kind regards, 

Marvin

  • 0
    TI__Mastermind 26485 points

    Hello Marvin,

      Noise parameters are separate from the S-parameters. These can be simulated using our Tina-Ti and PSpice models which can be found under the Design tools & simulation tab of our device product folders. We do not have an ADS specific model for this device, but I believe you may be able to import PSpice netlists into ADS. 

      Which device do you require 1-100MHz range? Our higher end RF amplifiers usually are tested in the higher frequency range, but I may be able to find more data for a specific device.

    Thank you,
    Sima 

  • 0 in reply to Sima Jalaleddine
    TI__Expert 5675 points

    Hi Sima, 

    Thank you for your response. Please see the feedback from our customer.

    “Thank you for your reply. It is indeed possible to import the PSpice netlists into ADS. I managed to do this for the OPA818 amplifier. However, are the simulation results I get with that model still valid for the 1-100 MHz range?

    As we are still deciding which amplifier to use, we do not have a specific device yet. Based on your experience, which one would you choose and why?”

    Please help to advise. Thank you for extending your support.

    Kind regards, 

    Marvin

  • 0 in reply to Marvin Cantos
    TI__Mastermind 26485 points

    Hello Marvin, 

       I'm glad it successfully imported! That is correct, the simulation results of the model will still be valid from DC to high frequencies which include 1-100MHz. 

       What are your design requirements (such as gain, bandwidth, input signal characteristics, output voltage range, loading, supply voltages) and application?  

    Thank you,

    Sima 

  • 0 in reply to Sima Jalaleddine
    TI__Expert 5675 points

    Hi Sima, 

    Thank you for your response. Please see the feedback from our customer.

    “Thank you for your reply, I am happy to hear that the model is also valid for lower frequencies and even DC.

    The most important parameters are low noise (i.e. NF<5dB) and high linearity (i.e. OIP3>30dB), the gain is less important but the aim is to get above 15 dB.

    Moreover, these parameters must be extremely constant/flat over the full frequency range of 1-100 MHz.

    The input signal is expected to have a large spread of voltage amplitudes, hence the required high linearity.

    The load will most probably just be referenced to 50 Ohms but can be adjusted if needed.

    Similarly, the idea is to use Vs+ = 5V and Vs- = -5V but this can be modified as well.

    I hope this gives you sufficient info to give us some recommendations.”

    Please help to advise. Thank you for extending your support.

    Kind regards, 

    Marvin

  • 0 in reply to Marvin Cantos
    TI__Mastermind 19096 points

    Hello Marvin,

    Thank you for sharing your customer's design requirements.  We will examine the details and work on a response for you to share.

    Best,

    Alec

  • 0 in reply to Marvin Cantos
    TI__Expert 8540 points

    Hi Marvin, 

    Apologies for the delayed response. The OPA855 is going to be the best amplifier for this application. It has a low noise performance of 0.98 nV/rtHz which is approximately 3.2 dB Noise Figure with a 50 Ohm source (not accounting for feedback and gain resistor noise). It has plenty of bandwidth and I'd expect should have OIP3 performance that should meet the requirement depending on the output voltage. That would have to measured specifically, but can easily be done with our evaluation module. 

    Regards, 

    Jacob