
6
μ
PC2709T
TEST CIRCUIT
COMPONENTS OF TEST CIRCUIT FOR
MEASURING ELECTRICAL CHARACTERISTICS
EXAMPLE OF ACTURAL APPLICATION COMPONENTS
Type
Value
Type
Value
Operating Frequency
C
3
Capacitor
1 000 pF
C1 to C3
Chip Capacitor
1 000 pF
100 MHz or higher
L
Bias Tee
1 000 nH
L
Chip Inductor
300 nH
10 MHz or higher
C
1
to C
2
Bias Tee
1 000 pF
100 nH
100 MHz or higher
10 nH
1.0 GHz or higher
INDUCTOR FOR THE OUTPUT PIN
The internal output transistor of this IC consumes 20 mA, to output medium power. To supply current for output
transistor, connect an inductor between the V
CC
pin (pin 6) and output pin (pin 4). Select large value inductance, as
listed above.
The inductor has both DC and AC effects. In terms of DC, the inductor biases the output transistor with minimum
voltage drop to output enable high level. In terms of AC, the inductor make output-port impedance higher to get
enough gain. In this case, large inductance and Q is suitable.
CAPACITORS FOR THE V
CC
, INPUT AND OUTPUT PINS
Capacitors of 1 000 pF are recommendable as the bypass capacitor for the V
CC
pin and the coupling capacitors
for the input and output pins.
The bypass capacitor connected to the V
CC
pin is used to minimize ground impedance of V
CC
pin. So, stable bias
can be supplied against V
CC
fluctuation.
The coupling capacitors, connected to the input and output pins, are used to cut the DC and minimize RF serial
impedance. Their capacitance are therefore selected as lower impedance against a 50
load. The capacitors thus
perform as high pass filters, suppressing low frequencies to DC.
To obtain a flat gain from 100 MHz upwards, 1 000 pF capacitors are used in the test circuit. In the case of under
10 MHz operation, increase the value of coupling capacitor such as 10 000 pF. Because the coupling capacitors are
determined by equation, C = 1/(2
π
Rfc).
V
CC
1 000 pF
1 000 pF
1 000 pF
C
1
C
2
L
4
6
1
2, 3, 5
50
50
OUT
IN
C
3