
TC32306FTG
2015-10-01
19
6.4 Local Oscillator
6.4.1 Local Oscillation Abstracts
Table 6-13 Local Oscillation Abstracts
Item
Function
Reference Clock Frequency
30.32MHz (Fixed)
PLL
Fractional - N PLL
VCO Frequency
1732 - 1896MHz
Divider
1/6, 1/4, 1/2 (Setting three stages)
Local Frequency
315, 434, 868 / 915 MHz
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.
Fig 6-7 Case of Reference Clock Circuit
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.
Table 6-14 RF Frequency & Division Ratio
h'0A[D1]
BAND1
h'0A[D0]
BAND0
RF Frequency Band
Division Ratio
0
0
315MHz
6
0
1
434MHz
4
1
X
868 / 915MHz
2
X: Don’t care
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
X_ OUT
X_IN
XOSC
Xtal
Crystal
XOSC
Signal Source
X_OUT
X_IN
External Signal Source