RF5924_1 Datasheet, PDF (8/14 Pages) RF Micro Devices – 3.7V, SINGLE-BAND FRONT-END MODULE

RF5924
Theory of Operation
The RF5924 FEM is a single-chip integrated front-end module (FEM) for high performance WLAN applications in the 2.4GHz to
2.5GHz ISM band. The FEM addresses the need for aggressive size reduction for a typical 802.11b/g RF front-end design and
greatly reduces the number of components outside of the core chipset therefore minimizing the footprint and assembly cost of
the overall 802.11b/g solution. The FEM has integrated b/g power amplifier, power detector, RX balun and TX filtering. Also it is
capable of switching between WLAN RX, WLAN TX, and BTH RX/TX operations. It has low insertion loss at the 2.4GHz to
2.5GHz WLAN and BTH paths. The device is manufactured on a laminate module and GaAs HBT processes. The device is pro-
vided in a 3.5mmx3.5mm, 16-pin package. This module meets or exceeds the RF front-end needs of 802.11b/g WLAN RF sys-
tems.
The RF5924 is designed primarily for IEEE802.11 b/g WLAN applications where the available supply voltage and current are
limited. The RF5924 requires a single positive supply voltage (V_CC), positive current control bias (PA_EN) supply, and a positive
supply for switch control to simplify bias requirements. The RF5924 FEM also has built in power detection. All inputs and out-
puts are internally matched to 50Ω except the WLAN receive path it is deferential with nominal impedance of 100 ohm on
each pin.
802.11b/g Transmit Path
The RF5924 has a typical gain of 30dB from 2.4GHz to 2.5GHz, and delivers 16dBm typical output power under 54Mbps
OFDM modulation and 20.5dBm under 11Mbps CCK modulation. The RF5924 requires a single positive supply of 3.1V to
4.5V to operate at full specifications. Current control optimization for the 802.11b/g band is provided through one bias control
input pin (PA_EN). The PA_EN pin requires a regulated supply to maintain nominal bias current. In general, higher PA_EN volt-
age produce higher linear output power, higher operating current, and higher gain.
Out of Band Rejection
The RF5924 contains basic filtering components to produce bandpass responses for the transmit and receive paths. Due to
space constraints inside the module, filtering is limited to a few resonant poles per RF path. Additional filters may need to be
added outside the module depending upon the end-user's application.
802.11b/g Receive Path
The 802.11b/g path has a100Ω differential impedance with a nominal insertion loss of 1.8dB. The RX port return loss is 10db
minimum. The RX Balun is manufactured on Integrated GaAs Process. Depending on the application, if filtering is required
beyond what the RF5924 can achieve then additional external filters will need to be added outside of the RF5924.
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