rf3145 RF Micro Devices, rf3145 Datasheet - Page 17

• Manufacturer Part Number: rf3145
• Description: Quad-band Gsm/edge/gsm850/dcs/pcs Power Amplifier Module Rf3145
• Manufacturer: RF Micro Devices

Harmonics are natural products of high efficiency power amplifier design. An ideal class “E” saturated power amplifier will pro-
duce 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 pro-
cess, 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 represent the maximum power of the har-
monics throughout the transmit chain. This is based on proper harmonic termination of the transmit port. The receive port ter-
mination 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 DS050919
RAMP
From DAC
to correspond with the battery voltage.
*Shaded area eliminated with Indirect Closed Loop using RF3145
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at ([phone] or [e-mail].
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