tea5764hn-n2 NXP Semiconductors, tea5764hn-n2 Datasheet - Page 7

• Manufacturer Part Number: tea5764hn-n2
• Description: Fm Radio + Rds
• Manufacturer: NXP Semiconductors

Philips Semiconductors
TEA5764HN_2
Product data sheet
8.4 Crystal oscillator
8.5 PLL tuning system
The crystal oscillator can operate with a 32.768 kHz clock crystal. The oscillator can be
overridden via the FREFIN pin. When the FREFIN pin is used the oscillator is clocked
externally by a 32.768 kHz signal. Selection between a reference clock or a reference
crystal can be done via the I
left open-circuit, and when pin FREFIN is used a crystal may not be connected. It is not
possible to connect a crystal and apply a frequency via the FREFIN pin in the same
application.
The crystal oscillator generates the reference frequency for the following:
The PLL synthesizer tuning system is suitable to operate with a 32.768 kHz reference
frequency generated by the crystal oscillator or a reference clock of 32.768 kHz fed into
the TEA5764HN. To tune the radio to the required frequency requires the PLL word to be
calculated and then programmed to the register. The PLL word is 14 bits long; see
Table 20
Formula for high-side injection:
Formula for low-side injection:
where:
Example for receiving a channel at 100.1 MHz:
N
N
N
•
•
•
•
•
•
DEC
DEC
N
f
f
f
DEC
RF
IF
ref
DEC
Reference frequency divider for synthesizer PLL
Timing for the IF counter
Timing for the pause detector
Free running frequency adjustment of the stereo decoder VCO
Centre frequency for adjustment of the IF filters
Clock frequency of the RDS/RBDS decoder
= intermediate frequency of 225 kHz
= the reference frequency of 32.768 kHz
= wanted tuning frequency (Hz)
=
=
=
= decimal value of PLL word
and
4
------------------------------------- -
4
------------------------------------- -
4
----------------------------------------------------------------------- -
Table
100.1 10
f
f
f
f
RF
RF
ref
ref
+
–
21. Calculation of this 14-bit word can be done as follows.
f
f
32768
IF
IF
Rev. 02 — 9 August 2005
6
+
225 10
2
C-bus. When a crystal is connected the FREFIN pin must be
3
=
12246.704
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
TEA5764HN
FM radio + RDS
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