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RF5765

DS120213

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

The RF5765 Front End Module (FEM) is designed for WiFi applications in the 2.5GHz ISM band. It can be applied in many por-

table applications such as handsets, Portable Media Players, and portable battery power equipment. This highly integrated

module can be connected directly to the battery without additional voltage regulators.

WiFi TRANSMIT MODE

maintain nominal bias current. The RF5765 transmit path has a typical gain of 30dB from 2.4GHz to 2.5GHz, and delivers

20dBm typical output power under 54Mbps OFDM modulation and 23dBm under 1Mbps 11b modulation. The RF5765 con-

tains basic filter components to produce a bandpass response for the transmit path. Due to space constraints inside the mod-

ule, filtering is limited to a few resonant poles and additional filters may be required depending upon the end-user’s

application. While in transmit mode, the active components are the Power Amplifier (PA) and the TX branch of the SP3T switch.

Refer to the logic control table for proper settings.

TX Biasing Instructions

• Connect the TX input (pin-1) to a signal generator and a spectrum analyzer at the Antenna output (pin-10)

aged.

• The SP3T controls for the off branches (C_RX and C_BT) must be set to a logic “low” (0.2V max) or grounded. In the event

that one of these branches is left floating or in a logic “high” the performance of the PA will degrade significantly. Likewise,

unused RF Ports must be terminated in 50Ω to simulate actual system conditions and prevent RF signals from coupling

back to the PA.

•Turn RF ON

WiFi RECEIVE MODE

Within the frequency band of operation 2.4GHz to 2.5GHz, the RF5765 WiFi receive path has a typical gain of 18dB and a NF

of 2.1dB with about 10mA of current. In RX mode, only the RX branch of the SP3T and the LNA are active. Refer to the logic

control table for proper settings.

RX Biasing Instructions

• Connect the RX input (ANT/pin-10) to a signal generator and a spectrum analyzer at the RX output (pin-3). A VNA may be

used as well.

• Turn the LNA bias ON (pin-4) and set the voltage to 3.3V

• Set C_RX (pin-6) high. This turns ON the receive branch of the SP3T.

that one of these branches is left floating or in a logic “high” the performance will degrade. It is recommended to terminate

unused RF Ports in 50Ω.

• Set the control bias for the SPST switch (C_BWRX/pin-5) “low” during WiFi RX only mode.

•Turn RF ON