
2-91
RF2128P
Rev A4 990216
2
P
Pin
1
Function
VCC2
Description
Power supply for the driver stage and interstage matching. External
matching on this pin is required to optimize the gain. The matching on
this port also greatly affects the input impedance. A decoupling capaci-
tor of 330pF is required, together with a series RC for tuning for maxi-
mum gain at the desired frequency. See the application information for
details.
Ground connection for the driver stage. Keep traces physically short
and connect immediately to the ground plane for best performance.
Power Down control. When this pin is "low", all circuits are shut off. A
"low" is typical 1.2V or less at room temperature. When this pin is
"high", all circuits are operating normally. A "high" is V
CC
. If PD is below
V
CC
output power and performance will be degraded. This could be
used to obtain some gain control, but results are not guaranteed.
RF Input. This is a 50
input, but the actual impedance depends on the
matching provided on pin 1. An external DC blocking capacitor is
required if this port is connected to a DC path to ground.
Ground connection for the output stage. Keep traces physically short
and connect immediately to the ground plane for best performance.
RF Output and power supply for the output stage. Bias for the output
stage needs to be provided on this pin. This can be done through a
quarter-wave microstrip that is RF grounded on the other end. For
matching to 50
, an external series microstrip line is required.
Same as pin 6.
Interface Schematic
2
GND1
3
PD
4
RF IN
5
GND2
6
RF OUT
7
8
RF OUT
VCC1
Power supply for the bias circuits. An external RF bypass capacitor of
22pF is required. Keep the traces to the capacitor as short as possible,
and connect the capacitor immediately to the ground plane.
Ground connection. The backside of the package should be connected
to the ground plane through a short path, i.e., vias under the device
may be required.
Pkg
Base
GND
1
2
3
4
8
7
6
5
BIAS
CIRCUITS
PACKAGE BASE
GND
330 pF
22 pF
8 pF
2 pF
VPD
(PCB mat'l: FR-4,
Thickness: 0.031")
22 pF
100
, 200 mil
L=100 mil,
W=20 mil
67
, 0.20"
33 pF
50
μ
strip
L=100 mil
L=220 mil,
W=10 mil
V
CC
RF OUT
RF IN