RF7115 datasheet(11/22 Pages) RFMD

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RF7115

Rev A0 DS060808

7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical

support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.

Theory of Operation

Product Description

The RF7115 is a high-power, high-efficiency, transmit module (TXM) with fully-integrated power control functionality, harmonic

filtering, band selectivity, and TX/RX switching. The TXM is self-contained, with 50

Ω I/O terminals with four RX ports allowing

true quad band operation. The power control function eliminates all power control circuitry, including directional couplers,

diode detectors, and power control ASIC’s, etc. The power control capability provides 50dB continuous control range, and

70dB total control range, using a DAC-compatible, analog voltage input. The TX Enable feature provides for PA activation (TX

mode) or RX mode/Stand-by. Internal switching provides a low-loss, low-distortion path from the Antenna port to the TX path (or

RX port), while maintaining proper isolation. Integrated filtering provides ETSI compliant harmonic suppression at the antenna

port even under high mismatch conditions, which is important as modern antennas today often present a load that signifi-

cantly deviates from nominal impedance.

Overview

The RF7115 is a true quad-band GSM850, EGSM900, DCS1800, and PCS1900 power amplifier module with fully integrated

power control functionality, harmonic filtering, band selectivity and TX/RX switching. This simplifies the phone design by elimi-

nating the need for the complicated control loop design, harmonic filters, TX/RX switch and possible matching components

between these. The power control loop can be driven directly from the DAC output in the baseband circuit. The module has 4

Rx ports for GSM850. EGSM900, DCS1800, and PCS1900 bands of operation. For optimum performance, it is best to use Rx1

and Rx2 for low band, and Rx3 and Rx4 for high band operation. Best forward isolation can be achieved in these states during

the off mode as well. To control the mode of operation, there are four logic control signals; TX Enable, B1, B2, and B3. Refer to

truth table below for mode of operations. If control signals are limited, eliminate the use of the standby mode and B3 may

remain in the high state for all modes of operation. By also changing the don’t care state (X) of B1 allows minimum control

logic switching between on and off states.

Module Control and Antenna Switch Logic

TX_EN

B1B2B3

TX Module Mode

Stand by mode

RX 1

RX 2

RX 3

RX 4

TX low band (GSM850/EGSM900)

TX high band (DCS1800/PCS1900)

RF7115 Datasheet(PDF) 11 Page - RF Micro Devices