TDA7478_11 Datasheet, PDF (8/11 Pages) STMicroelectronics – Single chip RDS demodulator

Oscillator controls (FSEL, OSEL)
4
Oscillator controls (FSEL, OSEL)
TDA7478
Two different crystal frequencies can be used. The adaption of the internal clock divider to
the external crystal is achieved via the input pin FSEL. See the following table for reference.
Table 6. Crystal frequencies
Crystal
FSEL (pin configuration)
4.332MHz
8.664MHz
connected to GND or open
connected to Vs
A special mode is introduced to reduce EMI. With pin OSEL connected to GND the internal
oscillator is switched off and an external sinusoidal frequency could be applied on OSCIN.
The peak to peak voltage of this signal can be reduced down to 60 mV.
In this mode the frequency selection via FSEL is still active.
Suggested values of C1 and C2 are shown in the following table.
Table 7. C1 and C2 suggested value
Crystal
C1
4.332MHz
8.664MHz
27pF
27pF
C2
47pF
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Doc 10679 Rev 3