RF3159 Просмотр технического описания (PDF) - RF Micro Devices
Номер в каталоге
Компоненты Описание
производитель
RF3159 Datasheet PDF : 26 Pages
| |||
RF3159
Modes of Operation
The RF3159 is a dual-mode saturated GSM and linear EDGE Power Amplifier. In GSM mode, the RF3159 is a traditional Power-
Star® module, which means that the output power is controlled by the VRAMP voltage. In EDGE mode, the RF3159 acts as a
gain block where the output power is controlled by the input RF power. The input RF drive level is reduced from GSM mode to
prevent saturation and limit output power. Figure 1 shows the Power Amplifier operating regions in GSM and EDGE mode.
35 dBm
P1 dB
29 dBm
GSM
GMSK
EDGE
8-PSK
Linear Operation
Saturated Operation
Input Power
Figure 1. RF3159 Power Amplifier Operating Regions in GSM/EDGE Mode
GSM applications typically require an input RF drive that is 3dB to 4dB higher than the 1dB compression point. GSM mode
involves GMSK modulation, which is a constant envelope modulation and is not sensitive to amplitude non-linearities caused
by the PA. Since the useful data in the GMSK modulation is entirely included in the phase, the amplifier may be operated in
saturated mode (deep class AB) for optimum efficiency. Saturated output power for the RF3159 is controlled by the voltage on
the VRAMP pin.
Linear EDGE applications require a linear power amplifier to transfer 8PSK modulation with minimal distortion. Since an 8PSK
signal has information encoded in both amplitude and phase, the use of a saturated PA is not trivial and requires a more com-
plex system. The traditional way to design a transmitter that is required to convey both phase and amplitude modulation is
through the use of a linear power amplifier (Class A). In the RF3159, the bias is held at a constant level such that the device is
operating in linear region, and the output RF level is directly proportional to the input RF level. The RF3159 is used as a linear
amplifier by selecting low or high bias mode by a digital signal on the VBIAS pin and reducing the input power to the PA such that
the device enters a linear operational region. Output power is controlled by applying the proper amplitude signal to the RF input
terminal.
Rev A0 DS070102
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
17 of 26
Share Link: 