question about SMD Cs

  • I want to modify a couple of UMTS PAs and I need SMD Cs 0805 What do I need for SMD Cs there are many different types NP0 and so on and how much voltage do they have to have

    The PA works with 28 volts

    Especially for the output circuit

  • Hallo Achim

    It,s for the HF path, i have found a Johanson Trimmer whit 1,4 - 4 pf in my Boxes that works very well and have 250 volt Spannungsfestigkeit. But what for Typs nid i for fest Condensator,s

    Greats Klaus

  • For the RF path I would settle for nothing less then ATC capacitors. You may use a trimmer for finding the initial setpoint but I would then measure the capacitance and replace it with a suitable ATC type cap (maybe even two in parallel to reduce ESR). Lowest ESR @ GHz and therefore small losses, little self-heating. Both desired for RF output path.