MC44BS373CADR2 datasheet(35/52 Pages) FREESCALE

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MC44BS373CA Data Sheet

Application Diagrams

18.4 BiCMOS Modulator QFN20 Stereo Application

Figure 18. Proposed QFN20 Package (Stereo Application Schematic)

Notes:

14. Cx value depends on crystal characteristics; Cx = 27 pF on Motorola application board.

15. RF PLL loop filter components at pin 16 must be as close as possible to FCC at pin 17.

16. Supply voltage decoupling capacitors must be as close as possible to ground.

17. For a stereo application, the audio signal is already encoded in the baseband stereo encoder. It is not necessary to

create a pre-emphasis and in this case the pre-emphasis capacitor has to be removed. Sometimes for the same

application it is useful to increase the FM deviation by replacing the original pre-emphasis capacitor with a 100-nF

capacitor. Adding this value boosts the deviation and does not create a pre-emphasis.

18. It is possible to create a peak for the low frequencies (from 30 to 80 Hz) by adjusting the sound loop filter resistor.

A flat response is given with a value of 5.6 K

Ω but this value can be set to 4.7 KΩ. This gives a peak of about 1 dB

at 40 Hz and extends the low-frequency cut-off at 28 Hz (see audio section).

19. Chip address select pin open (default I2C address = 0xCA)

The value of the audio input series capacitor has been increased in order to have a lower cut-off frequency.

TVOUT

2.2k

22nF

1nF

10nF

47nF

Vcc

SCL

SDA

4MHz

Vcc

Pre-em

GND

TVOVCC

LOP

TVOUT

Audio

Video

LOP

10 nF

1 uF

1uF

220nF

100nF

470pF

XTAL

GND

PREEM

10nF

Note 14

3K9 to 6K2

Note 15

Note 16

CAS

Note 19

Note 18

Note 17

MC44BS373CADR2 Datasheet(PDF) 35 Page - Freescale Semiconductor, Inc

MC44BS373CADR2 Datasheet(HTML) 35 Page - Freescale Semiconductor, Inc

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