RF2174
Typical Test Setup
Power Supply
V- S- S+ V+
RF Generator
Spectrum
Analyzer
3dB
10dB/5W
Buffer
x1 OpAmp
Pulse
Generator
A buffer amplifier is recommended because the current into
the VAPC changes with voltage. As an alternative, the voltage
may be monitored with an oscilloscope.
Notes about testing the RF2174
The test setup shown above includes two attenuators. The 3dB pad at the input is to minimize the effects that the switching
of the input impedance of the PA has on the signal generator. When VAPC is switched quickly, the resulting input impedance
change can cause the signal generator to vary its output signal, either in output level or in frequency. Instead of an attenuator
an isolator may also be used. The attenuator at the output is to prevent damage to the spectrum analyzer, and should be able
to handle the power.
It is important not to exceed the rated supply current and output power. When testing the device at higher than nominal sup-
ply voltage, the VAPC should be adjusted to avoid the output power exceeding +36dBm. During load-pull testing at the output
it is important to monitor the forward power through a directional coupler. The forward power should not exceed +36dBm,
and VAPC needs to be adjusted accordingly. This simulates the behavior for the power control loop in this respect. To avoid
damage, it is recommended to set the power supply to limiting the current during the burst, not to exceed the maximum cur-
rent rating.
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
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Rev A8 DS060918
RFMD [ RF MICRO DEVICES ]
