RF60 Datasheet, PDF (53/157 Pages) –

RF60 CRYSTAL-LESS SOC TRANSMITTER v1.0
13. LC Oscillator (LCOSC)
The RF60 VCO is a fully integrated CMOS LC oscillator that operates at approximately 3.9 GHz. This
block in conjunction with a programmable frequency divider generates the transmit carrier frequency.
The technology behind the VCO forms the core of the RF60s' crystal-less operation. After this device
is factory trimmed, the VCO fre- quency is the most accurate frequency on the chip and sets the chips
transmit frequency stability unless an external crystal oscillator is used. The device achieves ±150 ppm
frequency stability over the commercial temperature range of 0 to 70°C and ±250 ppm frequency stability
over the industrial temperature range of -
40 to 85°C.
The transmit carrier frequency is set by using the API functions vFCast_Tune (desired carrier) and
vFCast_Setup(). For FSK modulation, the frequency deviation is also a parameter to the freq_adjustment
function. Users are recommended to use the API functions to set the SFR register.
13.1. Register Description
SFR Definition 13.1. LC_FSK
Bit
7
6
5
4
3
2
1
0
Name ^RESERVED
FSK_DEVIATION[6:0]
Type
R/W
R/W
Reset
0
0
0
0
0
0
0
0
SFR Address = 0xE4
Bit Name
Function
7 RESERVED Reserved.
Do not write to this bit.
6:0 FSK_ FSK Deviation
DEVIATION These bits determine the FSK deviation. The values of these bits are calculated and
[6:0] ^{entered from the API Frequency Tune Module functions}
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