RF5111 Datasheet, PDF (12/14 Pages) RF Micro Devices – 3V DCS POWER AMPLIFIER

RF5111
Typical Test Setup
Power Supply
V- S- S+ V+
RF Generator
3dB
10dB/5W
Spectrum
Analyzer
Pulse
Generator
Buffer
x1 OpAmp
A buffer amplifier is recommended because the current into the
V_APC changes with voltage. As an alternative, the voltage may be
monitored with an oscilloscope.
Notes about testing the RF5111
The test setup shown above includes two attenuators. The 3dB pad at the input is to minimize the effects that the switch-
ing of the input impedance of the PA has on the signal generator. When V_APC 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 ana-
lyzer, 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
supply voltage, the V_APC 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 V_APC 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 current rating.
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Rev A1 060921