AX5131-TSSOP20-TU AXSEM, AX5131-TSSOP20-TU Datasheet - Page 17

• Manufacturer Part Number: AX5131-TSSOP20-TU
• Description: RF Transmitter TSSOP-Class-IC
• Manufacturer: AXSEM
• Type: Single Chip Transceiverr

Specifications of AX5131-TSSOP20-TU

• Package / Case: TSSOP-20
• Operating Frequency: 400 MHz to 940 MHz
• Maximum Operating Temperature: + 60 C
• Mounting Style: SMD/SMT
• Operating Supply Voltage: 2.2 V to 3.6 V
• Supply Current: 100 mA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

5.1.
The
internal circuitry at pin VREG from the primary supply VDD_IO. All VDD pins of the device must
be connected to VREG. The antenna pins ANTP and ANTN must be DC biased to VREG. The
I/O level of the digital pins is VDD_IO.
The voltage regulator requires a 1µF low ESR capacitor at pin VREG.
In power-down mode the voltage regulator typically outputs 1.7V at VREG, if it is powered-up
its output rises to typically 2.5V. At device power-up the regulator is in power-down mode.
The voltage regulator must be powered-up before transmit operations can be initiated. This is
handled automatically when programming the device modes via the
Register
above 1.3 V or 2.3 V, sticky versions of the bits are provided that can be used to detect low
power events (brown-out detection).
5.2.
The on-chip crystal oscillator allows the use of an inexpensive quartz crystal as the RF
generation subsystem’s timing reference. Although a wider range of crystal frequencies can
be handled by the crystal oscillator circuit, it is recommended to use 16 MHz as reference
frequency since this choice allows all the typical SRD band RF frequencies to be generated.
The oscillator circuit is enabled by programming the
enabled.
To adjust the circuit’s characteristics to the quartz crystal being used without using additional
external components, both the transconductance and the tuning capacitance of the crystal
oscillator can be programmed.
The transconductance is programmed via register bits XTALOSCGM[3:0] in register XTALOSC.
The integrated programmable tuning capacitor bank makes it possible to connect the
oscillator directly to pins CLK16N and CLK16P without the need for external capacitors. It is
programmed using bits XTALCAP[5:0] in register XTALCAP.
Version 1.0
AX5131
Voltage Regulator
Crystal Oscillator
VREG
uses an on-chip voltage regulator to create a stable supply voltage for the
contains status bits that can be read to check if the regulated voltage is
PWRMODE
register. At power-up it is not
PWRMODE
Circuit Description
Datasheet AX5131
register.
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