Video ICs
Electronic viewfinder driver
BA7149F
The BA7149F is an electronic viewfinder driver for video cameras. It separates the synchronous signal from the input
video signal, and outputs the vertical deflection drive output and horizontal deflection signals. HD and VD output sig-
nals with guaranteed phase difference are also provided for on-screen displays (OSD). The differences between the
BA7149F and the BA7148F are the horizontal blanking, horizontal AFC output, HD output phase and pulse width.
•
Applications
Video cameras
•
Features off a 5V power supply.
1) Operates
2) Built-in vertical deflection circuit.
3) Built-in wide-bandwidth amplifier.
4) Built-in HD and VD output terminals.
5) Few attached components required.
6) SOP 16pin package.
7) Compatible with 10µ sec flyback pulses.
•
Absolute maximum ratings (Ta = 25°C)
Parameter
Applied voltage
Power dissipation
Operating temperature
Storage temperature
Symbol
V
CC Max.
Pd
Topr
Tstg
Limits
8.0
500
∗
– 20 ~ + 75
– 55 ~ + 125
Unit
V
mW
°C
°C
∗
Reduced by 5mW for each increase in Ta of 1°C over 25°C.
•
Recommended operating conditions (Ta = 25°C)
Parameter
Power supply voltage
Symbol
V
CC
Min.
4.5
Typ.
5.0
Max.
5.5
Unit
V
1
Video ICs
BA7149F
•
Block diagram
16
15
14
13
12
11
10
9
H.OSC
PHASE
COMP
6dB
AMP
SYNC
SEPA
V.SEPA
H.BLK
V.BLK
V.DRIVE
V.OSC
1
2
3
4
5
6
7
8
•
Pin descriptions
Pin No.
1
2
3
4
5
6
7
8
Function
Vertical control input
Power supply 1
Vertical deflection drive (POS)
GND 1
Vertical deflection drive (NEG)
Vertical oscillator external resistor
Vertical oscillator external capacitor
VD output
Pin No.
9
10
11
12
13
14
15
16
HD output
GND 2
Video input
Power supply 2
Video output
Phase comparator output
Horizontal oscillator external resistor
Horizontal AFC output
Function
2
Video ICs
BA7149F
•
Electrical characteristics (unless otherwise noted, Ta = 25°C and Vcc = 5.0V)
Parameter
Operating current dissipation
Symbol
I
CC
Min.
31.0
Typ.
42.0
Max.
55.0
Unit
mA
〈
VIDEO AMP
〉
Voltage gain
D range
Frequency characteristic
Minimum sync separation voltage
Horizontal blanking width
Vertical blanking width
G
V
D
RV
f
C
V
syn · Min.
T
H · BL
T
V · BL
5.3
3.20
– 2.0
—
9.6
870
6.0
3.50
0.0
45
10.7
970
6.7
—
+ 2.0
120
11.4
1070
dB
V
P-P
dB
mV
P-P
µs
µs
〈
Horizontal
〉
Free-running frequency
Capture range
AFC output pulse width
AFC lock-in phase
Pulse voltage low
f
H · O
∆f
CAP
T
HP
T
HPH
V
HPL
13.9
±
2.1
10.2
– 1.9
0.5
15.7
±
3.0
11.1
– 1.2
1.1
17.5
—
12.0
– 0.5
1.7
kHz
kHz
µs
µs
V
〈
Vertical
〉
Free-running frequency
Pin 3 maximum output amplitude
Pin 5 maximum output amplitude
f
V · O
V
VP · Max.
V
VN · Max.
51.3
2.10
2.10
54.8
2.70
2.70
58.2
—
—
Hz
V
P-P
V
P-P
µs
µs
µs
V
V
〈
H
D
· V
D
〉
Phase difference
H
D
pulse width
V pulse width
Pulse voltage low
Pulse voltage high
Not designed for radiation resistance.
T
HVD
T
HD
T
VD
V
HV · L
V
HV · H
17.3
8.7
860
—
4.7
21.3
9.9
960
0.1
4.9
25.3
11.1
1060
0.3
—
3
Video ICs
BA7149F
•
Input / output circuits
1pin
12pin
2, 3, 4, 5pin
2pin
6pin
12pin
10k
V
+
2.33V
300
3pin
5pin
2k
V
+
500
500
1.9k
2k
1.5V
300
1pin
4pin
12k
6pin
Fig.1
Fig.2
Fig.3
7pin
12pin
5k
5k
5k
8pin
2pin
20k
12pin
8µA
7pin
10k
20k
8pin
9pin
2pin
10k
20k
25k
9pin
20k
20k
Fig.4
Fig.5
Fig.6
13pin
12pin
3k
100
11pin
11pin
50
12pin
14pin
12pin
3k
3k 3k 3k
13pin
1mA
100
V
14pin
1k
+
1.87V
36µA
1.25k
3k
3k 3k 3k
100
100
Fig.7
Fig.8
Fig.9
4
Video ICs
BA7149F
15pin
12pin
16pin
2pin
12pin
20k
20k
500
16pin
10k 10k 10k
12k
V
+
2k
2k
15pin
2.8V
Fig.10
Fig.11
operation
•
Circuitsignals
Input
Pulse IH
IH
63.556µ
H Pulse only
0.29V at 11pin
H Pulse only
Pulse IS
adj.at 11pin
4.7µ
262.5H
Pulse IV
16.683m
V Pulse only
Fig.12
The video signal input to pin 11 is detected by the charg-
ing and discharging of an external capacitor. Sync sepa-
ration is done in the SYNC SEPA block. The H. SYNC
signal is sent to the H. OSC, and the V. SYNC signal is
sync-separated in the vertical sync pulse interval and sup-
plied to the V. OSC block.
The H. OSC block consists of a PLL that oscillates in sync
with the sync-separated H. SYNC signal, and outputs the
HD pulse and horizontal deflection pulse.
In the V. OSC block, a direct-control method is used with
the sync signal. To synchronize the vertical oscillator cir-
cuit, the inherent oscillation period of the oscillation circuit
is made slightly larger than the vertical sync signal period,
so that the sync signal always enters slightly early.
The oscillator output alone is not enough to ensure stable
operation for the vertical deflection output circuit, so it is
amplified by the V. DRIVE block.
The horizontal and vertical blanking signals generated in
the H. OSC and V. OSC blocks are used to erase the hor-
izontal retrace line from the video signal input to pin 11.
The signal is inverted and amplified by a 6dB inverting
amplifier and output as a negative-polarity video signal.
5
