mc1377 Freescale Semiconductor, Inc, mc1377 Datasheet - Page 4

• Manufacturer Part Number: mc1377
• Description: Color Television Rgb To Pal/ntsc Encoder
• Manufacturer: Freescale Semiconductor, Inc

3
4
R
15 F
Burst
Flag
27k
18k
16
13
Buffer
Amp/
Chroma
0.1
Regulator
Out
PAL/NTSC
Figure 2. Power Supply and V B
8.2V
Control
Figure 3. RGB Input Circuitry
Switch
0/180
NTSC
PAL
R–Y
Figure 4. Chroma Section
4
V CC = +12V
G
15 F
27k
18k
PAL
14
NTSC
PAL
RGB Matrix
B–Y
17
15
B–Y
B–Y
32mA
Oscillator
5
B
+90
15 F
27k
18k
18
R–Y
R–Y
100
–Y
FUNCTIONAL DESCRIPTION
Decoup
Quad
19
9
6
MC1377
–Y
Power Supply and V B (8.2 V Regulator)
From the supply voltage applied to this pin, the IC biases
internal output stages and is used to power the 8.2 V internal
regulator (V B at Pin 16) which biases the majority of internal
circuitry. The regulator will provide a nominal 8.2 V and is
capable of 10 mA before degradation of performance. An
equivalent circuit of the supply and regulator is shown in
Figure 2.
R, G, B Inputs
10 k
input circuitry at Pins 3, 4, and 5.
tilt during the 50/60 Hz vertical period. However, if it is desired
to avoid the use of the capacitors, then inputs to Pins 3, 4,
and 5 can be dc coupled provided that the signal levels are
always between 2.2 V and 4.4 V.
the matrix circuitry which outputs the R–Y, B–Y, and –Y
signals. The –Y information is routed out at Pin 6 to an
external delay line (typically 400 ns).
DSBSC Modulators and 3.58 MHz Oscillator
I/Q Axes, Figure 22) from the matrix circuitry are amplitude
modulated onto the 3.58/4.43 MHz subcarrier. These signals
are added and color burst is included to produce composite
chroma available at Pin 13. These functions plus others,
depending on whether NTSC or PAL operation is chosen, are
performed in the chroma section. Figure 4 shows a block
diagram of the chroma section.
regardless of which mode is chosen (NTSC or PAL), the
mixers always perform the same operation. The B–Y mixer
modulates the color subcarrier directly, the R–Y mixer
receives a 90 phase shifted color subcarrier before being
modulated by the R–Y baseband information. Additional
operations are then performed on these two signals to make
them NTSC or PAL compatible.
an inverted burst of 3.58 MHz to be added only to the B–Y
signal. A gating pulse or “burst flag” from the timing section
permits color burst to be added to the B–Y signal. This color
burst is 180 from the B–Y signal and 90 away from the R–Y
signal (see Figure 22) and permits decoding of the color
information. These signals are then added and amplified
before being output, at Pin 13, to be bandpassed and then
reintroduced to the IC at Pin 10.
inverted 4.43 MHz burst to be added to both R–Y and B–Y
equally to produce the characteristic PAL 225 /135 burst
phase. Also, the R–Y information is switched alternately from
180 to 0 of its original position and added to the B–Y
information to be amplified and output.
The MC1377 pin for power supply connection is Pin 14.
The RGB inputs are internally biased to 3.3 V and provide
The input coupling capacitors of 15 F are used to prevent
After input, the separate RGB information is introduced to
The R–Y and B–Y outputs (see (B–Y)/(R–Y) Axes versus
The MC1377 has two double balanced mixers, and
In the NTSC mode, the NTSC/PAL control circuitry allows
In the PAL mode, NTSC/PAL control circuitry allows an
of input impedance. Figure 3 shows representative
MOTOROLA ANALOG IC DEVICE DATA