AX8052F151 datasheet(37/51 Pages) ONSEMI

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Transceiver

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AX8052F151

6.2. RF Input and Output Stage (ANTP/ANTN)

The AX8052F151 uses fully differential antenna pins. RX/TX switching is handled internally. An

external RX/TX switch is not required.

LNA

The LNA amplifies the differential RF signal from the antenna and buffers it to drive the I/Q mixer.

An external matching network is used to adapt the antenna impedance to the IC impedance. A DC

feed to the regulated supply voltage VREG must be provided at the antenna pins. For

recommendations, see section see the applications section.

I/Q Mixer

The RF signal from the LNA is mixed down to an IF of typically 1 MHz. I- and Q-IF signals are

buffered for the analog IF filter.

In TX mode the PA drives the signal generated by the frequency generation subsystem out to the

differential antenna terminals. The output power of the PA is programmed via bits TXRNG[3:0] in

the register

AX5051_TXPWR. Output power as well as harmonic content will depend on the

external impedance seen by the PA, recommendations are given in the applications section.

6.3. Analog IF Filter

The mixer is followed by a complex band-pass IF filter, which suppresses the down-mixed image

while the wanted signal is amplified. The center frequency of the filter is 1 MHz, with a passband

width of 1 MHz. The RF frequency generation subsystem must be programmed in such a way that

for all possible modulation schemes the IF frequency spectrum fits into the passband of the analog

filter.

6.4. Digital IF Channel Filter and Demodulator

The digital IF channel filter and the demodulator extract the data bit-stream from the incoming IF

signal. They must be programmed to match the modulation scheme as well as the data-rate.

Inaccurate programming will lead to loss of sensitivity.

The channel filter offers bandwidths of 40 kHz up to 600 kHz.

For detailed instructions how to program the digital channel filter and the demodulator see the

AX5051 Programming Manual, an overview of the registers involved is given in the following table.

The register setups typically must be done once at power-up of the device.

AX8052F151 Datasheet(PDF) 37 Page - ON Semiconductor