TDA5200 查看數據表（PDF） - Infineon Technologies

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TDA5200

ASK/FSK Single Conversion Receiver

Infineon Technologies 

TDA 5200

ASK Single Conversion Receiver

Applications

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 Chapter 5.1.3 and

by the quartz specifications given by the quartz manufacturer.

Crystal

CS

Input

impedance

Z1-28

Pin 28

TDA5200

Pin 1

Figure 8 Determination of Series Capacitance Value for the Quartz Oscillator

Crystal specified with load capacitance

CS

=

1

CL

1

+ 2π

f

XL

(4)

with CL the load capacitance (refer to the quartz crystal specification).

Examples

6.7 MHz

13.401 MHz

CL = 12 pF

CL = 12 pF

XL = 750 Ω

XL = 1250 Ω

CS = 8.7 pF

CS = 5.3 pF

These values may be obtained in high accuracy by putting two capacitors in series to the quartz, such as 20 pF

and 15 pF in the 6.7 MHz case and 15 pF and 8.2 pF in the 13.401 MHz case.

But please note that the calculated value of CS includes the parasitic capacitors also.

Data Sheet

25

Revision 3.0, 2010-12-28

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