RFFM3482E Datasheet, PDF (10/14 Pages) RF Micro Devices – 2.4GHz TO 2.5GHz SINGLE-BAND FRONT END MODULE

RFFM3482E
Theory of Operation
The RFFM3482E FEM is a single-chip integrated front end module (FEM) for high performance WiFi 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/n RF front end design,
and greatly reduces the number of components outside of the core chipset. Therefore, the footprint and assembly cost of the
overall 802.11b/g/n solution is minimized. The FEM has integrated b/g/n power amplifier, power detector, Rx balun, and Tx fil-
tering. Also, it is capable of switching between WiFi Rx, WiFi Tx, and BTH Rx/Tx operations. It has low insertion loss at the
2.4GHz to 2.5GHz WiFi and BTH paths. The device is manufactured in a GaAs pHEMT processes, and provided in a
3mmx3mmx0.45mm, 16-pin package. This module meets or exceeds the RF front end needs of 802.11b/g/n WiFi RF sys-
tems.
For best results, the PA circuit layout from the evaluation board should be copied as closely as possible, particularly the ground
layout and ground vias. Other configurations may also work, but the design process is much easier and quicker if the layout is
copied from the RFFM3482E evaluation board. There is an indicator pin labeled P1 ID that should be left as a no-connect on
the PCB. This pin is directly connected to the ground pad of the IC. For the best performance, it is recommended that voltage
and RF lines do not cross under this pin. Gerber files of RFMD PCBA designs can be provided on request. The supply voltage
lines should present an RF short to the FEM by using bypass capacitors on the VB traces. The RFFM3482E is a very easy part
to implement, but care in circuit layout and component selection is always advisable when designing circuits to operate at
2.5GHz. Please contact RFMD Sales or Application Engineering for additional data and guidance.
The RFFM3482E is designed primarily for IEEE802.11 b/g/n WiFi applications where the available supply voltage and current
are limited. The RFFM3482E requires a single positive supply voltage (VB), PA enable (PA_EN) supply, efficiency control (PABC),
and a positive supply for switch control to simplify bias requirements. The RFFM3482E FEM also has built in power detection.
All inputs and outputs are internally matched to 50 except the WiFi receive path it is deferential with nominal impedance of
100 on each pin.
802.11b/g/n Transmit Path
The RFFM3482E has a typical gain of 33dB from 2.4GHz to 2.5GHz, and delivers 16.5dBm typical output power under
54Mbps OFDM modulation, and 21dBm under 1Mbps 11b modulation. The RFFM3482E requires a single positive supply of
3.0V to 4.8V to operate at full specifications. PA control for the 802.11b/g/n 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, the PABC pin controls
acts as an efficiency and linearity control pin. The current or voltage applied at this pin may produce higher linear output
power, higher operating current, and higher gain.
Out of Band Rejection
The RFFM3482E contains basic filtering components to produce bandpass responses for the WiFi transmit path. Due to space
constraints inside the module, filtering is limited to a few resonant poles on the RF path.
802.11b/g/n Receive Path
The 802.11b/g/n path has a100 differential impedance with a nominal insertion loss of 2.1dB. The Rx port return loss is
-9dB maximum. Depending on the application, if filtering is required beyond what the RFFM3482E can achieve then additional
external filters will need to be added outside of the RFFM3482E.
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Prelim DS120109