1993_Motorola_Linear_Interface_ICs_Vol_2.pdf

24 Pin 28 Pin
(DIP) (SOIC)
1,21, 1,4,11,
23 18,24,
25,26
2 2
3 3
4 5
5 6
MC44301
Table 2. Pin Function Desription
Equivalent Internal Circuit
Vee
Vee
3.4k 1.8k
Vee
60 Positive
+--'WIo---o Video
Output
2.7k
60 Negative
+-_ ........ --0 Video
Output
1.6k
5.6k
1.0k Mode
Switch
AFT
.4.._+---0 Output
No Connection.
Functional Descrlptlonl
External Circuit Requirements
Positive Video Output
With White Spot Noise Inversion
In the evaluation PCB a discrete external buffer (2N4402)
is used to provide interface - this is not needed in the
actual application.
Negative Video Output
Without White Spot Noise Inversion
Intended for sync separator use.
MOTOROLA LINEAR/INTERFACE ICs DEVICE DATA
9-247
Mode Switch
Selects positive or negative modulation. The pin is open
for negative going video and grounded for positive
going video.
AFT Output
High output impedance push-pull current drive. Intended
to give high AFT loop gain when used with high load
impedances (i.e. direct connection to the tuner varactor
diode). Drive is greatly increased for large frequency error
to minimize pull-in time and clamped when PLL is not
locked. External circuitry is provided in the evaluation PCB
to allow adjustment of the drive to the tuner. This will not be
needed in the actual application where the tuner is
compatible with the IC. Polarity is controlled externally by
the AFT switch.
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