2
\$\begingroup\$

I've recently been researching various transceivers, but I run into trouble as soon as I get to the "typical applications" section of the data sheet.

With the Si4464 for instance, the example application provided does not specify recommended capacitor/inductor values. The circuit diagram (page 16) is provided below:

enter image description here

There are not footnotes provided for the figure. The figure is only referenced once in the entire document (page 15):

Figure 2 demonstrates an application for +20 dBm using an external T/R-switch.

My intuition tells me that the capacitor/inductor values are not specified because I am expected to know how to choose them myself. If that is the case, what principles should I use to determine the values? If not, am I missing some crucial information hidden in the data sheet?

\$\endgroup\$
5
  • \$\begingroup\$ Your intuition is correct. These sorts of devices are not intended for novices in the related field. \$\endgroup\$ Jun 4 '14 at 3:08
  • 2
    \$\begingroup\$ The Si4464 has a working RF range of 119-1050 Mhz. There is no possible way ever that you could have a antenna impedance matching network that worked well over that entire range without enormous complexity. \$\endgroup\$ Jun 4 '14 at 3:08
  • \$\begingroup\$ It's also worth noting that even if the datasheet did have part values, the actual part selection, and particularly the PCB layout requires a deep and intimate understanding of how the circuitry works anyways. RF PCB layout is non-trivial. \$\endgroup\$ Jun 4 '14 at 3:09
  • 4
    \$\begingroup\$ Often for these sorts of devices it's worth looking for development boards / reference designs to see if they match the frequency you're after. For example the following is for 915 MHz: silabs.com/products/wireless/Pages/RFMD-Reference-Design.aspx \$\endgroup\$
    – PeterJ
    Jun 4 '14 at 3:20
  • \$\begingroup\$ You might also want to read AN643: silabs.com/Support%20Documents/TechnicalDocs/AN643.pdf, specifically chapter 4. \$\endgroup\$
    – Tom L.
    Jun 4 '14 at 9:13

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.