4-273
RF2334
Rev A10 030415
Evaluation Board Schematic
(Download Bill of Materials from www.rfmd.com.)
Pin
Function
Description
Interface Schematic
1GND
Ground connection. For best performance, keep traces physically short
and connect immediately to ground plane.
2GND
Same as pin 1.
3RF IN
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.
4GND
Same as pin 1.
5RF OUT
RF output and bias pin. Biasing is accomplished with an external series
resistor and choke inductor to VCC. 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:
Care should also be taken in the resistor selection to ensure that the
current into the part never exceeds 68mA 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 4.8V 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.
R
V
SUPPLY
V
DEVICE
–
()
I
CC
-------------------------------------------------------
=
RF OUT
RF IN
1
2
3
5
4
C2
100 pF
C1
100 pF
50
Ω μstrip
50
Ω μstrip
J2
RF OUT
J1
RF IN
L1
100 nH
R1
22
Ω
VCC
P1-1
C3
100 pF
C4
1
μF
233X410-
P1
1
2
3
P1-1
VCC
GND
NC
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