TDK5101F_07 INFINEON [Infineon Technologies AG], TDK5101F_07 Datasheet - Page 26

• Manufacturer Part Number: TDK5101F_07
• Description: 315 MHz ASK/FSK Transmitter in 10-pin Package
• Manufacturer: INFINEON [Infineon Technologies AG]

3.8
Application Hints on the crystal oscillator
The crystal oscillator achieves a turn on time less than 1 msec when the specified crystal
is used. To achieve this, a NIC oscillator type is implemented in the TDK 5101 F. The
input impedance of this oscillator is a negative resistance in series to an inductance.
Therefore the load capacitance of the crystal CL (specified by the crystal supplier) is
transformed to the capacitance Cv.
Figure 14
Formula 1:
CL:
ω:
L:
Example for the ASK-Mode:
Referring to the application circuit, in ASK-Mode the capacitance C2 is replaced by a
short to ground. Assume a crystal frequency of 9.84MHz and a crystal load capacitance
of CL = 12 pF. The inductance L at 9.84 MHz is about 4.6 µH. Therefore C1 is calculated
to 10 pF.
Data Sheet
crystal load capacitance for nominal frequency
angular frequency
inductance of the crystal oscillator
Application Hints on the Crystal Oscillator
Application Hints
-R
Cv
Cv
=
L
IC
CL
=
1
CL
1
+
26
1
ω
+
1
2
ω
L
2
f, CL Cv
L
=
C
1
V 1.3, 2007-09-19
Applications
TDK5101F