MMIC (op-amp) vs transistor amplifier noise

Discussion in 'Wireless & RF Design' started by Synaps3, Apr 24, 2015.

  1. Synaps3

    Thread Starter Member

    Jun 5, 2013
    67
    2
    What type of amplifier typically has more noise, a MMIC or a transistor amplifier? Most of the MMICs seem to have a noise figure around 3dB. What is the noise figure for a transistor amplifier?

    In other words, if I'm looking to design an amplifier with the lowest noise possible, should I use an MMIC or transistor type amplifier?
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,137
    1,786
    Have you ever designed either type of amplifier before in the microwave band? What is your impression of your ability to do a discrete design? Do you have appropriate design tools? How about fabrication equipment? Will it be surface mount or Manhattan style dead bugs?
     
  3. Synaps3

    Thread Starter Member

    Jun 5, 2013
    67
    2
    No. This is a theoretical question. I'm definitely not skilled enough to do that. I'm looking at buying an amplifier right now that uses a lot of MMICs and I'm concerned about the noise figure.
     
  4. Papabravo

    Expert

    Feb 24, 2006
    10,137
    1,786
    OK, so on a theoretical basis what do you think are the primary sources of noise?
     
  5. seanstevens

    Member

    Sep 22, 2009
    25
    1
    In my experience, MMICs are generally noisier, you rarely find one much lower then 3dB noise level. They are however very easy to design and work with since they have 50 Ohm in/out impedance.

    If you are after low noise figures, transistor types and in particular GASFET are very low noise some with sub 1dB figures but they are not easy to design and are easily damaged by static and atmospheric charges etc.
     
  6. alfacliff

    Well-Known Member

    Dec 13, 2013
    2,449
    428
    there are gasfet and mesfet based mmics with low noise. not all are bipolar. check the latest from minicircuits labs.
     
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