TDK5100FXT Infineon Technologies, TDK5100FXT Datasheet - Page 25

• Manufacturer Part Number: TDK5100FXT
• Manufacturer: Infineon Technologies

Specifications of TDK5100FXT

• Operating Temperature (min): -40C
• Operating Temperature (max): 125C
• Operating Temperature Classification: Automotive
• Operating Supply Voltage (min): 2.1V
• Operating Supply Voltage (typ): 2.5/3.3V
• Lead Free Status / Rohs Status: Compliant

3.7
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 5100 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 13.56MHz and a crystal load capacitance
of CL = 12 pF. The inductance L at 13.56MHz 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
CL
IC
=
1
CL
1
+
25
1
ω
+
1
2
ω
L
2
L
=
f, CL Cv
C
1
V 1.2, 2008-04-04
Applications
TDK5100F