RF2418
Pin
10
Function Description
Interface Schematic
Same as pin 2.
GND
Mixer RF Input port. For a 50Ω match at 900MHz use a 15nH series
inductor. This pin is NOT internally DC-blocked. An external blocking
capacitor must be provided if the pin is connected to a device with DC
present. A DC path to ground (i.e. an inductor or resistor to ground) is,
however, acceptable at this pin. If a blocking capacitor is required, a
value of 22pF is recommended.To minimize the mixer’s noise figure, it
is recommended to have a RF bandpass filter before this input. This will
prevent the noise at the image frequency from being converted to the
IF.
11
RF IN
RF IN
Same as pin 2.
12
13
14
GND
GND
LNA OUT
Same as pin 2.
50Ω output. Internally DC-blocked.
LNA OUT
Application Schematic
High Impedance 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
15 nH
100 nF
47 pF
10pF
1 nF
4 pF
IF Filter, Hi Z
BUFFER
MIXER
C1
IF OUT
LO IN
8
L1
10 nH
VDD
100 nF
L1 and C1 are picked to match the mixer's output impedance (4 kΩ II 10 pF) to the IF
filter's impedance, at the IF frequency. C1 also serves as a DC block, in case the IF filter
is not an open circuit at DC.
8-24
Rev A7 060203
RFMD [ RF MICRO DEVICES ]
