RF2046
Pin
1
Function Description
Interface Schematic
RF input pin. This pin is NOT internally DC-blocked. A DC-blocking
RF IN
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.
Ground connection. For best performance, keep traces physically short
and connect immediately to ground plane.
2
3
GND
RF output and bias pin. Biasing is accomplished with an external series
RF OUT
resistor and choke inductor to V . The resistor is selected to set the
CC
RF OUT
DC current into this pin to a desired level. The resistor value is deter-
mined by the following equation:
(VSUPPLY – VDEVICE
)
RF IN
R = ------------------------------------------------------
ICC
Care should also be taken in the resistor selection to ensure that the
current into the part never exceeds 35mA 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 3.5V 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.
Same as pin 2.
4
GND
Application Schematic
VCC
10 nF 22 pF
47 nH
4
RBIAS
22 pF
RF IN
1
3
RF OUT
22 pF
2
Rev A11 050207
4-175
RFMD [ RF MICRO DEVICES ]
