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Pin No.
5
6
7
8, 9
Video IF
Input
MOTOROLA ANALOG IC DEVICE DATA
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PIN FUNCTION DESCRIPTION (continued)
Equivalent Internal Circuit
V CC
V CC
60
1.0 mA
6
Negative Video Output
2.0 k
V CC
V CC
60
1.0 mA
6
Positive Video Output
2.0 k
Sound AFT Filter/
10
Peak White Filter
7
V CC
V CC
0 to
300 µA
PAL
SECAM
NTSC
V CC
3.4 k
8
9
MC44302A
Negative Video Output
Negative going video appears at this output and it is intended to
drive a sync separator. Positive going video will appear at this
output when Pin 3 is grounded. This feature provides a simple
means for descrambling the video signal in systems that use
alternate line video inversion. Refer to the description of Pin 3. The
video output is designed to drive a resistive load that is in the range
of 2.0 kΩ. Lower resistance values will tend to increase output
distortion.
3.4
1.2
Positive Video Output
Positive going video appears at this output and is intended to drive
the luma and chroma channels. Negative going video will appear
at this output when Pin 3 is grounded. This feature provides a
simple means for descrambling the video signal in systems that
use alternate line video inversion. Refer to the description of Pin 3.
The positive going video signal always contains white spot
inversion whether it appears at output Pins 5 or 6. The video
output is designed to drive a resistive load that is in the range of
2.0 kΩ. Lower resistance values could increase output distortion.
3.4
1.2
Sound AFT Filter/Peak White Filter
A capacitor connected from this pin to ground is used to adjust the
sound AFT time constant in PAL and NTSC modes, and video
V CC
peak white AGC time constant in SECAM mode. The sound AFT
filter voltage controls the internal tuning capacitance that is placed
across the sound quadrature coil at Pin 26. Refer to Figure 9.
Video IF Input
These pins are the inputs to the video IF amplifier. The amplifier
consists of four ac coupled stages with an input sensitivity of
40 µV for a 2.2 Vpp video output swing. This sensitivity eliminates
the need for a preamplifier when used with suitable surface
acoustic waves or passive block filters. The IF block filter must be
located close to the IC package inputs to prevent unwanted pickup
and possible instability problems. The input lead lengths must be
kept short with a symmetrical printed circuit board layout.
Description
19
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