AX5243 datasheet(37/65 Pages) ONSEMI

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Circuit Description

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AX5243

carrier signal. For AFC adjustment, the frequency offset can be computed with the

following formula:

XTAL

TRKRFFREQ





The pull-in range of the AFC can be programmed with the

MAXRFOFFSET Registers.

5.15. PWRMODE Register

The

PWRMODE register controls, which parts of the chip are operating.

PWRMODE

Name

Description

0000

POWERDOWN

All digital and analog functions, except the register file, are disabled. The core

supply voltages are switched off to conserve leakage power. Register

contents are preserved and accessible registers via SPI, but at a slower

speed.

Access to the FIFO is not possible and the contents are not preserved.

POWERDOWN mode is only entered once the FIFO is empty.

0001

DEEPSLEEP

AX5243 is fully turned off. All digital and analog functions are disabled. All

To leave DEEPSLEEP mode the pin SEL has to be pulled low. This will initiate

startup and reset of the AX5243. Then the MISO line should be polled, as it

will be held low during initialization and will rise to high at the end of the

initialization, when the chip becomes ready for operation.

0101

STANDBY

The crystal oscillator and the reference are powered on; receiver and

transmitter are off. Register contents are preserved and accessible registers

via SPI.

Access to the FIFO is not possible and the contents are not preserved.

STANDBY is only entered once the FIFO is empty.

0110

FIFO

The reference is powered on. Register contents are preserved and accessible

registers via SPI.

Access to the FIFO is possible and the contents are preserved.

1000

SYNTHRX

The synthesizer is running on the receive frequency. Transmitter and receiver

are still off. This mode is used to let the synthesizer settle on the correct

frequency for receive.

1001

FULLRX

Synthesizer and receiver are running.

1011

WOR

Receiver wakeup-on-radio mode.

The mode the same as POWERDOWN, but the 640 Hz internal low power

oscillator is running.

1100

SYNTHTX

The synthesizer is running on the transmit frequency. Transmitter and

receiver are still off. This mode is used to let the synthesizer settle on the

correct frequency for transmit.

1101

FULLTX

Synthesizer and transmitter are running. Do not switch into this mode before

the synthesizer has completely settled on the transmit frequency (in

SYNTHTX mode), otherwise spurious spectral transmissions will occur.

For the corresponding currents see table in section 4.2.

AX5243 Datasheet(PDF) 37 Page - ON Semiconductor

AX5243 Datasheet(HTML) 37 Page - ON Semiconductor

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