Extreme 220GHz+Broadband Silicon Capacitor X2SC 0201M 22nF BV11(pim.murata.com)
47 pointsby peter_d_sherman5 hours ago5 comments
  • thomasjb3 hours ago
    https://www.digikey.ie/en/products/detail/murata-electronics...

    A mere 2.40 euros each!

    • matherial2 hours ago
      All silicon capacitors are relatively expensive, they're specialty parts that generally go into expensive things (mmWave airport scanners, optical backhaul, etc).
      • TheJoeMan2 hours ago
        Did they build 5,000 airport scanners at once? MOQ is brutal!
        • IndrekRan hour ago
          One scanner has way more than one channel…
  • threatripper2 hours ago
    Figure 1 made me laugh out loud.
    • stn8188an hour ago
      It may seem overly simplistic, but 2-port models for capacitors can be configured in series (as shown here) or in shunt (much more common for power distribution network applications). So, as basic as you might think this diagram is, it is entirely expected to be there so that we instantly know if the S-parameters are in series or shunt configuration - it would be more unusual if it were missing.
    • aaronmdjones2 hours ago
      Same here. That's made my week.
      • tedd4uan hour ago
        1 •--||--• 2

        Figure 1 block diagram

  • dlcarrier2 hours ago
    Someone's actually using nF, instead of 0.022uF or 22,000pF.
    • PowerElectronix2 hours ago
      I never understood why nF is less frequently used than uF or pF. To me, the logical thing is to express the capacity in units that are between 1 and 1000, like it's done with resistors and inductors.
      • summa_tech10 minutes ago
        I, too, had wondered; this seems particularly common in the US. My best theory is that in rough handwriting, n and u/μ can look pretty similar, and everyone sort of agreed to only use u to reduce ambiguity.
  • lisper2 hours ago
    Why is this a component? Couldn't you just make one of these out of PCB traces?
    • bri3d2 hours ago
      Certainly not at these frequencies and corresponding high capacitance values; getting 22nF out of a PCB even with ECM would require quite a large surface area and at 220GHz you can't have that since your wavelength is so short; you'd just be making a giant resonator instead.
      • IndrekRan hour ago
        Length of this capacitor is close to half-wavelength of 220 GHz (in vacuum).

        Using siblings of this broadband capacitor (40 GHz, same package) in some designs. In assembly, those require decent process control. This 0201M package is closer to 01005 passives in pad size. Typically no solder paste is used, just flux. Solder mask alignment has to be very tight (thin web used as a dam only).

        Cost per cap is reasonable where it is actually needed, other parts of the system are often orders of magnitude more expensive at those frequencies where performance matters. Where it gets the very high performance, is pillars/channels etched into silicon quite similar to how DRAM capacitors are made, just a “little bit bigger”. This allows for very low inductance and thus very high resonant frequency.

      • Eduardan hour ago
        ECM = Embedded Capacitance Material.

        It is a special PCB laminate designed to create capacitance inside the PCB stack-up, typically between closely spaced power and ground planes.

    • matherial2 hours ago
      No, not if you want 22 nF. That's a pretty substantial capacitance. It would need to be quite big on a PCB. That would mean significant inductance, and thus, bad performance at high frequencies.
  • rayiner3 hours ago
    I love the block diagram lol.