RF2461PCBA-41X データシートの表示（PDF） - RF Micro Devices
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RF2461PCBA-41X Datasheet PDF : 14 Pages
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RF2461
L1, C1, and R form a current combiner which performs a differential to single-ended conversion at the IF frequency and sets
the output impedance. In most cases, the resonance frequency is independent of R and can be set according to the following
equation:
fIF =
1
2π L21(C1 + CEQ)
Where CEQ is the equivalent stray capacitance and capac-
itance looking into pins 11 and 12. An average value to
use for CEQ is 2.5pF to 3pF.
R can then be used to set the output impedance according to the following equation:
( ) R =
4
1
ROUT
-
1
RP
-1
L2 and C2 serve dual purposes. L2 serves as an output
bias choke, and C2 serves as a series DC block.
where ROUT is the desired output impedance and RP is the
parasitic equivalent parallel resistance of L1.
C1 should be chosen as high as possible (not greater
than 15pF), while maintaining an RP of L1 that allows for
the desired ROUT.
In addition, L2 and C2 may be chosen to form an imped-
ance matching network if the input impedance of the IF
filter is not equal to ROUT. Otherwise, L2 is chosen to be
large, and C2 is chosen to be large if a DC path to ground
is present in the IF filter, or omitted if the filter is DC
blocked.
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7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Rev B6 DS060925
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