AX5051-QFN28-TU AXSEM, AX5051-QFN28-TU Datasheet - Page 22

• Manufacturer Part Number: AX5051-QFN28-TU
• Description: RF Transceiver General-Purpose-IC
• Manufacturer: AXSEM

Specifications of AX5051-QFN28-TU

• Number Of Receivers: 1
• Number Of Transmitters: 1
• Wireless Frequency: 433 MHz, 868 MHz, 915 MHz
• Interface Type: SPI
• Output Power: 17 dBm
• Operating Supply Voltage: 2.2 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Maximum Supply Current: 100 mA
• Minimum Operating Temperature: - 40 C
• Modulation: ASK, FSK, PSK
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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Circuit Description
VCO
An on-chip VCO converts the control voltage generated by the charge pump and loop filter
into an output frequency. This frequency is used for transmit as well as for receive operation.
The frequency can be programmed in 1 Hz steps in the
433 MHz band, the BANDSEL bit in the
VCO Auto-Ranging
The
range for specific frequency generation subsystem settings automatically. Typically it has to
be executed after power-up. The function is initiated by setting the RNG_START bit in the
PLLRANGING
The RNGERR bit indicates the correct execution of the auto-ranging.
Loop Filter and Charge Pump
The
synthesizer loop band width. The loop-filter has three configurations that can be
programmed via the register bits FLT[1:0] in register PLLLOOP, the charge pump current can
be programmed using register bits PLLCPI[1:0] also in register PLLLOOP. Synthesizer
bandwidths are typically 50 - 500 kHz depending on the
section 4.3: AC Characteristics.
Registers
Register
PLLLOOP
FREQ
IFFREQHI, IFFREQLO
PLLRANGING
Version 1.9
3. Adaptation of the bandwidth to the data-rate. For transmission of FSK and MSK it is
AX5051
AX5051
required that the synthesizer bandwidth must be in the order of the data-rate.
FLT[1:0]
PLLCPI[2:0]
BANDSEL
has an integrated auto-ranging function, which allows to set the correct VCO
internal loop filter configuration together with the charge pump current sets the
register. The bit is readable and a 0 indicates the end of the ranging process.
Bits
Synthesizer loop filter bandwidth, recommended usage is to increase the bandwidth
for faster settling time, bandwidth increases of factor 2 and 5 are possible.
Synthesizer charge pump current, recommended usage is to decrease the bandwidth
(and improve the phase-noise) for low data-rate transmissions.
Switches between 868 MHz/915 MHz and 433 MHz bands
Programming of the carrier frequency
Programming of the IF frequency
Initiate VCO auto-ranging and check results
PLLLOOP
register must be programmed.
Purpose
FREQ
PLLLOOP
registers. For operation in the
settings, for details see the
Datasheet AX5051