SX1781 View Datasheet(PDF) - Semtech Corporation
Part Name
Description
MFG CO.
'SX1781' PDF : 16 Pages View PDF
SX1781
PLL Frequency Synthesizer with integrated VCO
ADVANCED COMMUNICATIONS & SENSING
FINAL
DATASHEET
Figure 5 offers the necessary bandwidth. Out_P and Out_N signal are shifted by +/- 90°, thus combining on the single
ended load, hence increasing the output power. The series inductors denoted Lp help cancel the parasitic capacitance of
the package connections and DC bias is provided via the choke inductor Lc.
Lp
Cb
Out_P
Lb
Lp
Cb
Out_N
Lb
CL
Lc
50 ohms
The following lumped elements values have shown to offer a reasonable output power over the 1.2 - 1.4 GHz range:
Label
Lp
Lb
Cb
Lc
Cl
Value
4.7
2.7
3.3
47
22
Unit
Comment
nH
Multilayer, its value sets the center frequency
nH
Multilayer
pF
COG
nH
Choke inductor, coil type
pF
AC link capacitor at 1.3 GHz
Rev 1 - November 2008
©2008 Semtech Corp.
Page 12
www.semtech.com
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