CD22204
Functional Block Diagram
BANDPASS
FILTERS
BAND
SPLIT
FILTERS
BS1
ZERO
CROSSING
DETECTORS
697
770
852
941
BS2
1209
1336
ATB 11
XEN
6
1477
1633
DV
12
DATA STROBE
CLOCK
GENERATOR
CHIP CLOCKS
2 D1
1M
1 D2
XOUT
9
POWER REGULATOR
VOLTAGE
REF
OUTPUT
DECODER
OUTPUT
REGISTER
14 D4
AMPLITUDE
DETECTORS
ANALOG
IN
7
PREPROCESSOR
60Hz
REJECT
PRE EMP
TIMING
CIRCUITRY
10
XIN
÷
8
13 D8
DATA CLEAR
3 EN
4
V
DD
8
V
SS
NOTE: Pin numbers are for plastic DIP.
System Functions
Analog In
The Analog In pin accepts the analog input. It is internally
biased so that the input signal may be either AC or DC
coupled, as long as it does not exceed the positive supply
voltage. Proper input coupling is illustrated below.
CD22204E
V
DD
The CD22204 is designed to accept sinusoidal input
waveforms, but will operate satisfactorily with any input that
has the correct fundamental frequency with harmonics that
are at least 20dB below the fundamental.
Crystal Oscillator
The CD22204 contains an on-board inverter with sufficient
gain to provide oscillation when connected to a low cost
television “color-burst” (3.579545MHz) crystal. The crystal
oscillator is enabled by tying XEN high. The crystal is
connected between XIN and XOUT. A 1MΩ resistor is also
connected between these pins in this mode. ATB is a clock
frequency output. Other CD22204 devices may use the
same frequency reference by tying their ATB pins to the ATB
output of a crystal connected device. XIN and XEN of the
auxiliary devices must then be tied high and low,
respectively. Up to ten devices may be run from a single
crystal connected CD22204 as shown in Figure 2.
0.01µF
AUDIO
INPUT
(+4dBm OR
1.22V
RMS
MAXIMUM)
270kΩ
7
(ON CHIP)
10pF
1500pF
33kΩ
ANALOG
IN
>100kΩ
V
SS
OPTIONAL
HIGH FREQUENCY
NOISE FILTER
(f
C
= 3.9kHz)
FIGURE 1. ANALOG IN
3
INTERSIL [ INTERSIL CORPORATION ]
