RF3159 Просмотр технического описания (PDF) - RF Micro Devices
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RF3159 Datasheet PDF : 26 Pages
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RF3159
RF3159 Power Amplifier
Simplified Block Diagram of a Single Band
TX_EN
VRAMP
VBATT
H(s)
AGC Amplifier
RF IN
TX_EN
RF OUT
Theory of Operation
Overview
The RF3159 is designed for use as the final RF amplifier in GSM850, EGSM900, DCS and PCS handheld digital cellular equip-
ment, and other applications operating in the 824MHz to 915MHz, and 1710MHz to 1910MHz bands. The RF3159 is a high
power, dual mode GSM/EDGE, power amplifier with PowerStar® integrated power control. The integrated power control cir-
cuitry provides reliable control of saturated power by a single analog voltage (VRAMP). This control voltage can be driven directly
from a DAC output. PowerStar®’s predictable power versus VRAMP relationship allows single-point calibration in each band. Sin-
gle-point calibration enables handset manufacturers to achieve simple and efficient phone calibration in production.
The RF3159 also features an integrated saturation detection circuit, which is an industry first for standard PA module prod-
ucts. The saturation detection circuit automatically monitors battery voltage, and adjusts the power control loop to reduce tran-
sient spectrum degradation that would otherwise occur at low battery voltage conditions. Prior to the implementation of the
saturation detection circuit, handset designers were required to adjust the ramp voltage within the system software. RFMD’s
saturation detection circuit reduces handset design time and ensures robust performance over broad operating conditions.
The design of a dual mode power amplifier module is a challenging process involving many performance trade-offs and com-
promises to allow it to perform well in both saturated and linear operating regions. This is most noticeable in the RF3159 GSM
efficiency. A GSM only part can have its load line (output match) adjusted for maximum efficiency. In a dual-mode module, tun-
ing of the load line must be balanced between GSM efficiency and EDGE linearity. The result is slightly lower GSM efficiency
than a single mode (saturated only) power amplifier module. In addition, the RF3159 uses a special GaAs Heterojunction Bipo-
lar Transistor (HBT) process technology which is not used in the most efficient GSM only power amplifiers. The special HBT pro-
cess allows the RF3159 to provide excellent linear performance, Error Vector Magnitude (EVM), and Adjacent Channel Power
Ratio (ACPR), yet maintain competitive GSM efficiency.
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7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Rev A0 DS070102
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