Component properties for >10MHz frequencies

Discussion in 'General Electronics Chat' started by user46, Feb 7, 2013.

  1. user46

    Thread Starter New Member

    Feb 7, 2013
    Hi, I'm pretty new to electric circuits so bare with me. I'm trying to doing some clamping, clipping with diodes and voltage follower on a signal with components up to 10MHz. For this I intend to use transistors, diodes and perhaps an op amp. My questions regards how I should choose my components. When simulating circuits in PSpice with regular parts, I get distortions (which I really want to avoid).

    What properties for transistors, diodes and op amps are important to avoid distortions for high frequencies and what values should they have in my case? For instance, I've heard about gain bandwidth, slew rate, rise time etc. Are there any suggestions on products that will work for my frequency? Can I get a distortion-free signal, or ought I expect that nothing is even close to ideal?
  2. chuckey

    Well-Known Member

    Jun 4, 2007
    10 MHZ is no big deal nowadays. But if you are selecting amplifiers the words to look for "video" or "RF", general purpose won't work. Gainbandwidth (GB) is as it says gain times bandwidth. So an amp with a 1GHZ gain band width should give you a gain of X 10 up to 100 MHZ, X100 up to 10MHZ, perhaps X1000 up to 1MHZ (depending what its ultimate gain is). Slew rate is the ability of an amplifier to give a high rate of change of output voltage. its the reciprocal of bandwidth ( X PI), which is when the response is down by 3 dB on the low frequency gain ( X.707). Rise time is similar. You should be able to get a signal which has distortion of less then .5 %.