RF2418
Application Schematic
Buffered Output Configuration
850MHz
10 nH
LNA
RF IN
1
2
3
4
5
6
7
14
13
12
11
10
9
Image Filter, 50 Ω
VDD
RF AMP
15nH
100 nF
47 pF
10pF
C1
R1
1 nF
4 pF
IF OUT
BUFFER
MIXER
IF Filter, 50Ω
LO IN
8
10 nH
R2
L1
VDD
L1 should parallel resonate, at the IF frequency, with the internal
10pF capacitor plus any extra parasitic layout capacitance.
100 nF
100 nF
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.
Rev A7 060203
8-25
RFMD [ RF MICRO DEVICES ]
