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RF2418
Rev A7 060203
Application Schematic
Buffered Output Configuration
850MHz
1
2
3
4
5
6
7
14
13
12
11
10
9
8
LNA
MIXER
BUFFER
10pF
RF AMP
IF Filter, 50
Ω
IF OUT
RF IN
Image Filter, 50
Ω
15nH
10 nH
LO IN
V
DD
V
DD
L1 should parallel resonate, at the IF frequency, with the internal
10pF capacitor plus any extra parasitic layout capacitance.
R1 and R2 are bias resistors that set the bias current for the buffer
amplifier. The value recommended is 510 W, each. Higher values
will decrease the current consumption but also decrease the output
level at which voltage clipping begins to occur. At lower IF
frequencies, where the internal 10 pF capacitor does not roll off the
conversion gain, L1 may be eliminated.
C1 is a blocking capacitor, in case the IF filter's input is not an open
circuit at DC.
10 nH
47 pF
100 nF
R1
C1
L1
R2
100 nF
100 nF
1 nF
4 pF