tea5766uk NXP Semiconductors, tea5766uk Datasheet - Page 7

• Manufacturer Part Number: tea5766uk
• Description: Tea5766uk Stereo Fm Radio + Rds
• Manufacturer: NXP Semiconductors

NXP Semiconductors
TEA5766UK_1
Product data sheet
7.6 Band limits
7.7 RF AGC
Formula for high-side injection:
Formula for low-side injection:
where:
Example for receiving a channel at 100.1 MHz:
Value 12246.704, is rounded down to the lowest integer value, being 12246, the PLL word
becomes 2FD6h.
The result found using
integer value (truncation). Via the control interface this value can be written to register
FRQSET and the TEA5766UK will then start an autonomous search beginning at this
frequency or go to a preset channel at this frequency. When the application is built
according to the application diagram of
tuning system will settle to the new frequency within 40 ms.
The PLL is triggered by writing one of the four bytes of the FRQSET and TNCTRL and
registers.
The Lock Detect (LD) bit in register TUNCHK will be set after PLL lock detection (see
Table
The TEA5766UK can be switched to the Japanese FM band or the US/Europe FM band.
Bit BLIM in register TNCTRL (see
(87.5 MHz to 108 MHz) and BLIM set to logic 1 enables the Japanese band (76 MHz to
90 MHz).
The RF AGC (or wideband AGC) prevents overloading and limits the amount of
intermodulation products created by strong adjacent channels. Default the RF AGC is on
and it can be turned off via the control interface.
The TEA5766UK also has an in-band AGC to prevent overloading by the wanted channel
itself. The in-band AGC is always on.
N
N
N
DEC
DEC
N
f
f
f
DEC
RF
IF
ref
DEC
= intermediate frequency of 225 kHz
= reference frequency of 32.768 kHz
= wanted tuning frequency (Hz)
18).
=
=
=
= decimal value of PLL word
4
------------------------------------- -
4
------------------------------------- -
4
----------------------------------------------------------------------- -
100.1 10
f
f
f
f
RF
RF
ref
ref
+
–
f
f
32768
IF
IF
Rev. 01 — 22 March 2007
Equation 1
6
+
225 10
Table
or
3
Equation 2
=
Figure 21
16) set to logic 0 enables the US/European band
12246.704
must always be rounded to the lowest
and with the preferred components, the
TEA5766UK
Stereo FM radio + RDS
© NXP B.V. 2007. All rights reserved.
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