Data Sheet PU10491EJ01V0DS
TEST CIRCUIT
The application circuits and their parameters are for reference only and are not intended for use in actual design-ins.
COMPONENTS OF TEST CIRCUIT FOR
MEASURING ELECTRICAL CHARACTERISTICS
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 VCC 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 makes output-port impedance higher to get
enough gain. In this case, large inductance and Q is suitable.
CAPACITORS FOR THE VCC, INPUT AND OUTPUT PINS
Capacitors of 1000 pF are recommendable as the bypass capacitor for the VCC pin and the coupling capacitors
for the input and output pins.
The bypass capacitor connected to the VCC pin is used to minimize ground impedance of VCC pin. So, stable bias
can be supplied against VCC fluctuation.
The coupling capacitors, connected to the input and output pins, are used to cut the DC and minimize RF serial
impedance. Their capacitances 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 Rfc).
