ROHM BA7149

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 signals 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
•1)Features
Operates off a 5V power supply.
5) Few attached components required.
6) SOP 16pin package.
7) Compatible with 10µ sec flyback pulses.
2) Built-in vertical deflection circuit.
3) Built-in wide-bandwidth amplifier.
4) Built-in HD and VD output terminals.
•Absolute maximum ratings (Ta = 25°C)
Parameter
Applied voltage
Symbol
Limits
Unit
VCC Max.
8.0
V
mW
Pd
500∗
Operating temperature
Topr
– 20 ~ + 75
°C
Storage temperature
Tstg
– 55 ~ + 125
°C
Power dissipation
∗ 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
Min.
Typ.
Max.
Unit
VCC
4.5
5.0
5.5
V
1
Video ICs
BA7149F
•Block diagram
16
15
H.OSC
14
13
PHASE
COMP
12
11
10
9
SYNC
SEPA
6dB
AMP
V.SEPA
H.BLK
V.BLK
V.DRIVE
1
2
3
V.OSC
4
5
6
7
8
•Pin descriptions
Pin No.
2
Function
Pin No.
Function
1
Vertical control input
9
HD output
2
Power supply 1
10
GND 2
3
Vertical deflection drive (POS)
11
Video input
4
GND 1
12
Power supply 2
5
Vertical deflection drive (NEG)
13
Video output
6
Vertical oscillator external resistor
14
Phase comparator output
7
Vertical oscillator external capacitor
15
Horizontal oscillator external resistor
8
VD output
16
Horizontal AFC output
Video ICs
BA7149F
•Electrical characteristics (unless otherwise noted, Ta = 25°C and Vcc = 5.0V)
Parameter
Operating current dissipation
Symbol
Min.
Typ.
Max.
Unit
ICC
31.0
42.0
55.0
mA
〈VIDEO AMP〉
Voltage gain
GV
5.3
6.0
6.7
dB
D range
DRV
3.20
3.50
—
VP-P
fC
– 2.0
0.0
+ 2.0
Vsyn · Min.
—
45
120
mVP-P
Horizontal blanking width
TH · BL
9.6
10.7
11.4
µs
Vertical blanking width
TV · BL
870
970
1070
µs
15.7
17.5
kHz
—
kHz
Frequency characteristic
Minimum sync separation voltage
dB
〈Horizontal〉
Free-running frequency
fH · O
Capture range
∆f CAP
13.9
± 2.1
± 3.0
µs
AFC output pulse width
THP
AFC lock-in phase
THPH
– 1.9
– 1.2
– 0.5
µs
Pulse voltage low
VHPL
0.5
1.1
1.7
V
10.2
11.1
12.0
〈Vertical〉
fV · O
51.3
54.8
58.2
Hz
Pin 3 maximum output amplitude
VVP · Max.
2.10
2.70
—
VP-P
Pin 5 maximum output amplitude
VVN · Max.
2.10
2.70
—
VP-P
Phase difference
THVD
17.3
21.3
25.3
µs
HD pulse width
THD
8.7
9.9
11.1
µs
V pulse width
TVD
860
960
1060
µs
Free-running frequency
〈HD · VD〉
Pulse voltage low
VHV · L
—
0.1
0.3
V
Pulse voltage high
VHV · H
4.7
4.9
—
V
䊊Not designed for radiation resistance.
3
Video ICs
BA7149F
•Input / output circuits
2, 3, 4, 5pin
1pin
6pin
2pin
12pin
10k
+
V
2.33V
500
500
12pin
300
3pin
5pin
1.9k
2k
V
+
2k
12k
1.5V
300
6pin
1pin
4pin
Fig.2
Fig.1
Fig.3
8pin
7pin
9pin
5k
2pin
2pin
12pin
5k
5k
20k
12pin
10k
8µA
20k
7pin
10k
8pin
20k
20k
Fig.5
Fig.4
Fig.6
14pin
11pin
13pin
12pin
3k
9pin
25k
20k
11pin
50
12pin
12pin
100
3k
3k 3k 3k
13pin
14pin
1mA
1k
100
V
+
1.87V
1.25k
36µA
3k
100
Fig.7
4
Fig.8
3k 3k 3k
100
Fig.9
Video ICs
BA7149F
16pin
15pin
2pin
12pin
12pin
20k
20k
10k 10k 10k
500
16pin
12k
V
+
2k
2k
15pin
2.8V
Fig.11
Fig.10
operation
•Circuit
Input signals
IH
63.556µ
Pulse IH
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 charging and discharging of an external capacitor. Sync separation 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 supplied 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 horizontal 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
Video ICs
BA7149F
•Application example
VIDEO OUT
VCC
VCC
VIDEO IN
FBT
100µ
15k
470
+ 1µ
100k
10k
1µ
+
470
47µ
0.022µ
1500pF
+
0.22µ
510k
+
390k
16
15
H.OSC
14
13
PHASE
COMP
12
HD
11
10
9
SYNC
SEPA
6dB
AMP
V.SEPA
H.BLK
V.BLK
V.DRIVE
VCC
1
2
V.OSC
3
4
5
6
7
15k
+
0.022µ
5mH + 36Ω
8
0.1µ
VD
47µ
VR1
100
3.9
Fig.13
∗1 The resistors connected to pins 6 and 15 should have a tolerance of ± 2%, and a temperature
coefficient of ± 100ppm or lower.
∗2 The capacitor connected to pin7 should have a tolerance of ± 5%, and a temperature coefficient of
± 250ppm or lower.
6
Video ICs
BA7149F
notes
•(1)Operation
H.OSC free-run frequency and capture range
The free-run frequency is determined by the 115kΩ
resistor connected between pin 15 and GND. The capture range is varied by the resistors and capacitor connected to pins 14 and 15.
The free-run frequency and capture range for this IC
are guaranteed for these circuit constant values, and
we recommend that you use them. The resistor 115kΩ
connected between pin15 and GND should have a tolerance of ± 2%, and a temperature coefficient of ±
100ppm or lower.
(2) V.OSC free-run frequency
The V.OSC free-run frequency is determined by the
15kΩ resistor connected between pin 6 and GND, and
the 0.1µF capacitor connected between pin 7 and
GND.
The free-run frequency and capture range for this IC
are guaranteed for these circuit constant values, and
we recommend that you use them. The resistor 15kΩ
connected between pin 6 and GND should have a tolerance of ± 2%, and a temperature coefficient of ±
100ppm or lower, and the capacitor connected
between pin 7 and GND should have a tolerance of ±
5%, and a temperature coefficient of ± 250ppm or
lower.
(3) Use with PAL systems
In PAL systems, change the value of the resistor connected between pin 6 and GND to 18kΩ.
(4) PCB pattern
The large-signal systems and small-signal systems in
the IC have been kept separate, and the external wring
must also be done in such a way to prevent interference from occurring. In particular, to prevent the FBT
return current from interfering with the V. OSC circuit
on pins 6 and 7, do not directly connect the pin 4 GND
and pin 6 and 7 GND.
G
FBT
∗ Do not connect pin 4 GND
to pin 6 and 7 GND.
VCC
1
16
2
15
3
14
4
13
5
12
6
11
7
10
8
9
Fig.14
•External dimensions (Units: mm)
16
9
1
8
1.27
0.4 ± 0.1
0.15 ± 0.1
4.4 ± 0.2
0.11
1.5 ± 0.1
6.2 ± 0.3
10.0 ± 0.2
0.3Min.
0.15
SOP16
7