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6.4 Local Oscillator
6.4.1
Local Oscillation Abstracts
Item
Reference Clock Frequency
PLL
VCO Frequency
Divider
Local Frequency
6.4.2
Reference Clock
Prepare 30.32MHz reference clock for TC32306FTG. To use crystal oscillator, connect it between X_IN
pin and X_OUT pin with load capacitors. This IC is designed and considered to connect a crystal
oscillator with the load capacitance of 6pF.
To use an external signal generator, for example TCXO, connect it to X_IN Pin via a coupling capacitor.
Also Open X_OUT Pin and keep input signal level range from 0.5 V to 1.5 V (Peak to peak). Don't
supply reference clock signal to external circuit from X_OUT pin.
X_ OUT
6.4.3
Local Oscillation
Local oscillator block consists of the fractional-N PLL, VCO and frequency divider. Local frequency is
the output of frequency divider. Select the division ratio for expected frequency band. Set
register:h'0A[D1:D0] and select the division ratio.
Set the integer counter and fractional counter of registers"h'0B[D7:D0], h'0C[D7:D0]" to set Local
frequency. When PLL is locked to the expected frequency, PLL_LD signal turns to be "H". To output
Table 6-13 Local Oscillation Abstracts
XOSC
X_IN
Xtal
Crystal
Fig 6-7 Case of Reference Clock Circuit
Table 6-14 RF Frequency & Division Ratio
h'0A[D1]
h'0A[D0]
BAND1
BAND0
0
0
0
1
1
X
Function
30.32MHz (Fixed)
Fractional - N PLL
1732 - 1896MHz
1/6, 1/4, 1/2 (Setting three stages)
315, 434, 868 / 915 MHz
X_ OUT
Signal Source
External Signal Source
RF Frequency Band
Division Ratio
315MHz
434MHz
868 / 915MHz
X: Don't care
19
TC32306FTG
XOSC
X_IN
6
4
2
2015-10-01
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