RF3145PCBA-41X RFMD [RF Micro Devices], RF3145PCBA-41X Datasheet - Page 17

• Manufacturer Part Number: RF3145PCBA-41X
• Description: QUAD-BAND GSM/EDGE/GSM850/DCS/PCS POWER AMPLIFIER MODULE
• Manufacturer: RFMD [RF Micro Devices]

Harmonics are natural products of high efficiency power amplifier design. An ideal class “E” saturated power amplifier
will produce a perfect square wave. Looking at the Fourier transform of a square wave reveals high harmonic content.
Although this is common to all power amplifiers, there are other factors that contribute to conducted harmonic content as
well. With most power control methods, a peak power diode detector is used to rectify and sense forward power. Through
the rectification process, there is additional squaring of the waveform resulting in higher harmonics. The RF3145
addresses this by eliminating the need for the detector diode. Therefore, the harmonics coming out of the PA should rep-
resent the maximum power of the harmonics throughout the transmit chain. This is based on proper harmonic termina-
tion of the transmit port. The receive port termination on the T/R switch, as well as the harmonic impedance from the
switch itself, will have an impact on harmonics. Should a problem arise, these terminations should be explored.
NOTE: Output power is limited by battery voltage. The relationship in Equation 4 does not limit output power. Equation 4
limits V
Rev A4 050919
From DAC
RAMP
to correspond with the battery voltage.
*Shaded area eliminated with Indirect Closed Loop using RF3145
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RF3145
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