RF2337
Pin
1
2
3
Function
GND
GND
RF IN
Description
Ground connection. Keep traces physically short and connect immedi-
ately to ground plane for best performance.
Same as pin 1.
RF input pin. This pin is NOT internally DC blocked. A DC blocking
capacitor, suitable for the frequency of operation, should be used in
most applications. DC coupling of the input is not allowed, because this
will override the internal feedback loop and cause temperature instabil-
ity.
Same as pin 1.
RF output and bias pin. Biasing is accomplished with an external series
resistor and choke inductor to V
CC
. The resistor is selected to set the
DC current into this pin to a desired level. The resistor value is deter-
mined by the following equation:
RF OUT
Interface Schematic
4
5
GND
RF OUT
4
RF IN
Care should also be taken in the resistor selection to
ensure that the
current into the part never exceeds 75mA over the planned oper-
ating temperature.
This means that a resistor between the supply and
this pin is always required, even if a supply near 3.6V is available, to
provide DC feedback to prevent thermal runaway. Because DC is
present on this pin, a DC blocking capacitor, suitable for the frequency
of operation, should be used in most applications. The supply side of
the bias network should also be well bypassed.
Evaluation Board Schematic
(Download Bill of Materials from www.rfmd.com.)
P1
P1-1
1
2
3
VCC
GND
NC
1
C1
100 pF
2
3
4
233X410-
VCC
P1-1
R1
22
Ω
L1
100 nH
5
C2
100 pF
C3
100 pF
C4
1
µF
50
Ω µstrip
J2
RF OUT
J1
RF IN
50
Ω µstrip
Rev A3 001201
4-157
GENERAL PURPOSE
AMPLIFIERS
(
V
SUPPLY
–
V
DEVICE
)
-
= ------------------------------------------------------
R
I
CC
RFMD [ RF MICRO DEVICES ]
