RF5110G Datasheet, PDF (13/18 Pages) RF Micro Devices – 3V GSM POWER AMPLIFIER

Typical Test Setup
Power Supply
V- V+ S+ S-
RF5110G
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 RF5110G
The test setup shown above includes two attenuators. The 3dB pad at the input is to minimize the effect on the signal
generator as a result of switching the input impedance of the PA. 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 sized accordingly 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. To
avoid damage, it is recommended to set the power supply to limit the current during the burst not to exceed the maximum
current rating.
Rev A3 060814
2-13