TDA5212_06 INFINEON [Infineon Technologies AG], TDA5212_06 Datasheet - Page 26

• Manufacturer Part Number: TDA5212_06
• Description: ASK/FSK 915MHz Single Conversion Receiver
• Manufacturer: INFINEON [Infineon Technologies AG]

Wireless Components
4.3 Crystal Load Capacitance Calculation
The value of the capacitor necessary to achieve that the crystal oscillator is
operating at the intended frequency is determined by the reactive part of the
negative resistance of the oscillator circuit as shown in Section 5.1.3 and by the
crystal specifications given by the crystal manufacturer.
Figure 4-4
Crystal specified with load capacitance
with C
Examples:
7.2 MHz:
14.5 MHz:
These values may be obtained in high accuracy by putting two capacitors in
series to the quartz, such as 18pF and 20pF in the 7.2MHz case and 18pF and
8.2pF in the 14.5MHz case. But please note that the calculated value for C
includes also all parasitic capacitors.
L
the load capacitance (refer to the crystal specification).
Determination of Series Capacitance Value for the Crystal Oscillator
C
C
L
L
= 12 pF
= 12 pF
4 - 5
Crystal
C
S
X
X
L
L
C
impedance
=
=500 Ω
=1050 Ω
Z
S
1-28
Input
C
1
L
+
2
1
π
TDA5212
f
Pin 1
Pin 28
C
C
X
S
S
L
= 9.5 pF
= 5.6 pF
Specification, December 2006
Applications
TDA 5212
Quartz_load_5212.wmf
S