TDA5204E1 Infineon Technologies, TDA5204E1 Datasheet - Page 24

• Manufacturer Part Number: TDA5204E1
• Description: ASK Single Conversion Receiver 390MHz
• Manufacturer: Infineon Technologies

Wireless Components
4.3 Quartz Load Capacitance Calculation
The value of the capacitor necessary to achieve that the quartz 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
quartz specifications given by the quartz manufacturer.
Figure 4-4
The quartz oscillator input impedance consists of a negative resistance and an
inductance L.
Crystal specified with load capacitance
with C
Examples with typ. values:
6.26 MHz:
12.52 MHz:
These values may be obtained by putting two capacitors in series to the quartz.
L
the load capacitance (refer to the quartz crystal specification).
Determination of Series Capacitance Value for the Quartz Oscillator
C
C
L
L
= 12 pF
= 12 pF
4 - 5
Crystal
C
S
L=21uH
L=19uH
=
C
impedance
Z
S
1-28
C
Input
1
L
+
(
2
1
π
f
TDA5204
Pin 1
)
Pin 28
C
C
2
S
S
L
= 8.6 pF
= 5 pF
Specification, January 2001
TDA 5204 E1
Applications
preliminary
Quartz_load.wmf