RF3375
Pin
1
Function
RF IN
Description
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 applica-
tions. DC coupling of the input is not allowed, because this will override the
internal feedback loop and cause temperature instability.
Ground connection.
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 determined by
the following equation:
Interface Schematic
2
3
GND
RF OUT
RF OUT
(
V
SUPPLY
–
V
DEVICE
)
R
=
------------------------------------------------------
-
I
CC
Care should also be taken in the resistor selection to ensure that the cur-
rent into the part never exceeds 80mA over the planned operating temper-
ature. This means that a resistor between the supply and this pin is always
required, even if a supply near 5.0V 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.
Ground connection.
RF IN
4
GND
Package Drawing
1.04
0.80
0.50
0.30
1.60
1.40
3.10
2.90
0.48
0.36
2 PL
4.60
4.40
2.60
2.40
1.80
1.45
1.75
1.40
Dimensions in mm.
Shaded lead is pin 1.
0.43
0.38
0.53
0.41
4 of 10
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Rev A7 DS050524
RFMD [ RF MICRO DEVICES ]
