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Upper Band Balun and Filter Needs Redesign #55

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TobiNakamura opened this issue May 4, 2018 · 6 comments
Open

Upper Band Balun and Filter Needs Redesign #55

TobiNakamura opened this issue May 4, 2018 · 6 comments
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@TobiNakamura
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Currently we are using Johanson Tech. 0915BM15A0001E integrated balun and filter (Center freq 915MHz). The required center frequency is 790MHz.
@TobiNakamura TobiNakamura added the Circuit Circuit design related label Jun 12, 2018
@Alenux55
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IIRC we want the center frequency around 790 MHz

@Alenux55
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Alenux55 commented Oct 2, 2018

How about 0783FB15A0100E filterbalun and match it to the CC1101? See CC1101 Design Note DN017 as well:
cc1101 output

@TobiNakamura
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Good idea.
Per DN017 (swra168a) the differential impedance at the CC1101 port looking towards the antenna is Z= 86.5 + j43 Ohm at 868/915 MHz.

@Alenux55
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Alenux55 commented Oct 2, 2018

I will see if TI happens to have the impedance data for 700-800 MHz

@Alenux55
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Alenux55 commented Oct 4, 2018

TI post

@Alenux55
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Alenux55 commented Oct 8, 2018

TI suggests two alternative filter baluns, the claim is that we only lose 0.25 dB extra gain to insertion loss

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@TobiNakamura @Alenux55