ROHM BA7230LS Datasheet
1
Multimedia ICs
NTSC color TV signal encoder
BA7230LS
The BA7230LS comprises an RGB signal matrix circuit, balanced modulator circuit (rectangular 2-phase modulation), oscillator circuit (VCXO) for a 3.58MHz subcarrier synchronized with video input burst signals, luminosity and
color difference signal mixing circuit, and a high speed switch for selecting composite signals of video input and RGB
input. RGB signals, synch signals, BFP (burst flag pulses), PCP (pedestal clamp pulses) are input, and an NTSC
composite signal is output.
•
Applications
Televisions (Teletext-capable), captain systems, video cameras, personal computers
•
Features
1) Allows superimposition of video images (VIDEO IN)
and computer images (RGB IN).
2) During superimposition, the subcarrier locked onto
the video input burst signal RGB is modulated with
the RGB signals by the APC circuit, preventing
unnatural color disturbance due to switching.
3) Both the RGB and video input signals are pedestalclamped, maintaining a natural image even during
fluctuation in luminosity.
4) Using a half down pulse, the video signal can be
reduced by 5dB to darken the background and
make the superimposed RGB image easier to see.
5) Carrier leak is suppressible to less than 70mV
P-P
(VOUT = 2VP-P) without adjustment.
6) Can be adapted for analog RGB input.
7) Compact 24-pin SZIP package minimizes external
components.
•
Block diagram
1
VIDEO OUT
3
Y IN
5
R-Y IN
7
VC
9
APC PHASE
ADJUSTMENT
11
VA
13
AR
15
AB
17
B-Y OUT
19
GND
21
PCP IN
23
YSP IN
2
SYNC IN
BA7230LS
4
B-Y IN
6
PD
8
VB
10
BURST LEVEL
ADJUSTMENT
12
BFP IN
14
AG
16
Y OUT
18
R-Y OUT
20
VIDEO IN
22
HDP IN
24
VCC
VCC
B - Y R - Y
+
HD
MATRIX
PD
VCXO
MOD MOD
+
2
Multimedia ICs BA7230LS
•
Input / output circuits
3 2 1 24 23 22
21
20
19
18
17
16
15121110
9
8
7
6
5
4
CLAMP
CLAMP
500Ω
5.6kΩ
1kΩ
9.1kΩ
10kΩ 15kΩ
15kΩ 7.5kΩ
15kΩ
10kΩ
10kΩ
500Ω
10kΩ
10kΩ
1kΩ
1kΩ
5.1kΩ
15kΩ
10kΩ
1.2kΩ
5.1kΩ
11kΩ
4.3kΩ
5kΩ
6.8kΩ
1kΩ
GND
15kΩ
3.2V 2.2V
V
CC
BA7230LS
VCC
3.4V
2.7V
2V
2V
1413
1kΩ
6.8kΩ
1V
Fig. 1
•
Absolute maximum ratings (Ta = 25°C)
•
Recommended operating conditions
Parameter Symbol Limits Unit
Power supply voltage 7.0 V
Power dissipation 500
∗
mW
Operating temperature
Storage temperature
°C
°C
– 20 ~ + 70
– 55 ~ + 125
V
CC
Pd
Topr
Tstg
∗
Reduced by 5.0mW for each increase in Ta of 1°C over 25°C.
Parameter Symbol Limits Unit
V
CC V4.5 ~ 5.5
VR VP-P0 ~ 0.7
VG VP-P0 ~ 0.7
VB VP-P0 ~ 0.7
VIN VP-P0 ~ 1.0
Power supply voltage
R input level
G input level
B input level
Video input level
3
Multimedia ICs BA7230LS
•
Electrical characteristics (unless otherwise noted, Ta = 25°C, VCC = 5.0V)
Parameter Symbol Min. Typ. Max. Conditions
Quiescent current I
Q
—3854mA —
Video output level V
OV
1.7 2.2 2.6 V
P-P
VIDEO IN = 1V
P-P
Half down level change GVH– 3 – 5 – 7 dB —
DC offset V
OF
— 50 160 mV
P-P
VIDEO IN = 1V
P-P
Crosstalk CT — – 46 – 40 dB VIDEO IN = 1V
P-P
V
R-Y
0.3 0.42 0.55 V
P-P
V
B-Y
0.2 0.31 0.42 V
P-P
YOUT output level V
Y
1.0 1.4 1.8 V
P-PVR
= VG = VB = 0.7V
P-P
Ys switching delay time T
D
— 60 — ns —
—SYNC output level V
OS
0.4 0.65 0.9 V
P-P
Burst output level VOB0.25 0.46 0.8 V
P-PRE
= 1.8k
Ω
Composite output level V
OY
1.7 2.2 2.6 V
P-PYIN
= 0.7V
P-P
G
R-Y
91113dB
G
B-Y
91113dB
G
R-B
— — 2 dB Difference between above gains
– 6 — 6 deg —
– 6 — 6 deg —
Carrier leak L
SC
—3070mV
P-PVOUT
= 2V
P-P
APC capture range f
CAP
±
100 — — Hz
Carrier phase range
φSC± 30±
45 — deg Superimposition
Video frequency characteristic f
V
4.5 6 — MHz – 3dB when f = 100kHz
Video output DG DG —
±
3.5 — % VIDEO IN = 1V
P-P
Video output DP DP —± 2.5 — deg VIDEO IN = 1V
P-P
Z
T
815—k
Ω
—
Input impedance (Ys) Z
TY
3 7.5 — k
Ω
—
V
T
0.9 2.0 2.8 V —
Threshold level (Ys) V
TY
0.5 1.1 1.8 V —
Unit
ER-EY output level
EB-EY output level
R-Y modulation gain
B-Y modulation gain
(R-Y) / (B-Y) modulation gain differential
(R-Y) / (B-Y) orthogonal phase shift
(R - Y) ·Burst orthogonal phase shift
Input impedance (SY, BF, PC, HD)
Threshold level (SY, BF, PC, HD)
V
R
= 0.7V
P-P
VB = 0.7V
P-P
R - YIN = 0.3V
P-P
B - YIN = 0.2V
P-P
Burst = 0.1V
P-P
, 2.8µS
∆
R
∆
B
Loading...