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RFFM4200

DS121008

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

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

Theory of Operation and Applications

The RFFM4200 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 greatly reduces the number of external components minimizing footprint and assembly cost of the

overall 802.11b/g/n solution. The RFFM4200 has an integrated b/g/n power amplifier, a power Detector, and TX filtering and

a Switch, which is capable of switching between WiFi RX, WiFi TX operations. The device is manufactured using InGaP HBT and

pHEMT processes on a 6mm x 6mm x 0.95mm laminate package. The module meets or exceeds the RF front-end needs of the

802.11b/g/n WiFi RF systems. The RFFM4200 is a very easy part to implement. To reduce the design and optimization pro-

cess on the customer application, the evaluation board layout should be copied as close as possible, in particular the ground

and via configurations. Gerber files of RFMD PCBA designs can be provided upon request. The supply voltage lines should

trol. The built-in Power Detector of the RFFM4200 can be used as power monitor in the system. All inputs and outputs are inter-

nally matched to 50Ω.

Transmit Path

The RFFM4200 has a typical gain of 34dB form 2.4GHz to 2.5GHz, and delivers 25.5dBm typical output power in 11n HT20

MCS7 and 26dBm typical in 11g 54Mbps. The RFFM4200 requires a single positive supply voltage of 5.0V to operate at full

Out of Band Rejection

The RFFM4200 contains a low pass filtering (LPF) to attenuate the 2nd Harmonics to -47dBm/MHz (typical), to meet the out of

band rejection requirements of the system for FCC specification.

Receive Path

The RX path has a 50Ω single-ended port. The receive port return loss is 9.6dB minimum. In this mode, the FEM has an Inser-

tion loss of 0.8dB and 30dB (typical) isolation to TX port.

RFFM4200 Biasing Instructions to the Evaluation Board

802.11b/g/n Transmit:

1. Connect the FEM to a signal generator at the input and a spectrum analyzer at the output. Set the Pin at signal generator is

at -20dBm.

the part may exceed device current limits.

the collector voltage significantly if long leads are used. Adjust the bias voltage to compensate.

5. Turn on RF of signal generator and gradually increase power level to the rated power. CAUTION: If the input signal exceeds

the rated power, the RFFM4200 evaluation board can be permanently damaged.

802.11b/g/n Receive:

• To receive WiFi set the switch control lines per the truth table.