EMRFD Message Archive 13625

Message Date From Subject
13625 2017-02-22 08:23:14 m5evt SMD inductor BPF for receiver
There are enough designs for SDRs in the open source domain using SMD inductors of various sizes for BPF receivers on the RX front end. However, has anyone performed any measurements to investigate the potential downsides of this compared with a toroid wound inductor? What about 0805 size vs 1206? I have the coilcraft type inductors in mind, not power inductors for switch-mode supplies.

I have the following in mind to cause me to question this:


My engineering judgment says that for a reasonably simple superhet with a moderately good mixer (IP3 in the region of +10 dBm), the only potential problem would be higher insertion loss from the filter?

I would welcome any comments or even better measurements!

73 de M5EVT
13628 2017-02-22 11:18:42 Clint Re: SMD inductor BPF for receiver
Recommend that you get some of the Coilcraft samples for Low Pass Filters – not sure if they have any band pass filters.  The frequency response of the low pass filters will give you a good idea as to what to expect from SMD inductors.  They also have response curves on their site.  You could also reverse model with the Elsie app to get a good idea as to the Q of the inductors.