Color Video Camera Synchronizing Signal Generator LSI
Pin Assignment Overview
The MN67621F generates color video camera synchronizing signals for the NTSC, PAL, and SECAM video
systems.
It divides the reference frequency to generate the horizontal synchronizing signal f
signal f
, and the composite synchronizing signal.
V
A built-in 4f
crystal oscillator circuit divides the fre-
SC
, the vertical synchronizing
H
quency by four to generate the color subcarrier frequency
signals SC1 and SC2.
Features
Supports CCDs with 420, 510, 590, and 670 H pixels
Supports NTSC, PAL, and SECAM video systems
PAL system 25Hz offset
Includes built-in oscillator circuit using external
crystal
Generates 14 signals, including the horizontal and
vertical synchronizing signals and the color
subcarrier frequency signals.
Power supply"H" level (5 V) power supply for horizontal and vertical
synchronizing signal circuits
Power supply"L" level (0 V) power supply for horizontal and vertical
synchronizing signal circuits
Power supply"H" level (5 V) power supply for color subcarrier circuits
Power supply"L" level (0 V) power supply for color subcarrier circuits
Connect these pins to a 4fSC crystal oscillator.
input
The pins have built-in feedback resistors.
If using an external clock, supply it to the OSCI pin and
input
leave the OSCO pin open.
Supply the reference clock for the horizontal and vertical
synchronizing signals.
NTSCPALSECAM
Television system
selection input
TVMD1"H""L""L"
TVMD2—"H""L"
The pins include built-in pull-up resistors.
420H510H590H670H
CCD scan lines
selection input
CCDS1"H""H""L""L"
CCDS2"H""L""H""L"
The pins include built-in pull-up resistors.
Test inputsKeep these pins at "L" level.
The pins include built-in pull-down resistors.
(B-Y) output
SC
This color subcarrier signal is formed by dividing the
crystal oscillator frequency (4f
) by four.
SC
Color subcarrier signal
If SC1 is the 180° signal, this signal has the following phase.
NTSC system: 90°
PAL system:90° when LSW is at "L" level
270° when LSW is at "H" level
Composite blanking signal
signal output
Vertical drive signal
Wide HD signal
Preblanking signal
Composite blanking signal
output
Signal for erasing video signal
Horizontal drive signal
Clamp pulses for luminance and color difference signals
Horizontal deflection start pulses
Page 4
MN67621FFor Video Equipment
Pin Descriptions (continued)
Pin No.SymbolPin NameFunction Description
9WBLKComposite wide blanking
output
20BFIDPOutput for burst flag/
identification signal
6PBLKComposite preblanking
output
21LSWLine switch signal
output
23FMTPTrigger signal output
24SCBLKSubcarrier blanking
signal output
40EOPhase comparator
output
Composite wide blanking signal
This pin produces blanking pulses wider than the CELK
pulses for both horizontal and vertical synchronization.
For NTSC and PAL systems, this is the burst flag (BF)
output, which gates the color subcarrier signal.
For the SECAM system, this is the identification (IDP)
signal, which switches the subcarrier waveform.
Composite preblanking signal
This pin produces blanking pulses narrower than the CBLK
pulses for both horizontal and vertical synchronization.
Line switch signal
The chip generates this signal for each horizontal scan line.
During NTSC operation, this pin remains at "L" level.
This pin provides the FM demodulator trigger signal for the
SECAM system.
During NTSC operation, this pin remains at "L" level.
This pin provides the signal for erasing the subcarrier signal
for the SECAM system.
During NTSC operation, this pin remains at "L" level.
Phase comparator output
Operating Modes
(1) Television system
TVMD1TVMD2
NTSCH—
PALLH
SECAMLL
(2) CCD pixels and reference clock (CLK) frequencies
CCDCLK frequency (MHz)Frequency divider ratio
pixels
420HHH
510HHL
590HLH
670HLL
CCDS1CCDS2
NTSCPAL/SECAMfor first stage
15.89160616.09375
(1010fH)(1030fH)
9.5349649.65625
(606fH)(618fH)
22.24824922.53125
(1414fH)(1442fH)
25.42657025.75000
(1616fH)(1648fH)
1/5
1/3
1/7
1/8
Page 5
For Video EquipmentMN67621F
H Decoder Pulse Timing Chart for NTSC
H-SYNC
CSYNC EO
V-SER
BF
CBLK
HD
WHD
CP2
PBLK
WBLK
–9.12
–4.72
–1.57
(
*
2.20
1
)
4.720
5.357.87
7.24
8.50
9.44
1H=63.55µs
Unit: µs
17.52
1
*
420 H : 2.33
510 H : 2.31
590 H : 2.34
670 H : 2.36
Page 6
MN67621FFor Video Equipment
Pulse Timing Chart for NTSC Composite and Vertical Synchronizing Signals (1/2)