ROHM BH7634AS Datasheet
1
Multimedia ICs
Audio / video switch for CANAL - Plus
decoder
BH7634AS
The BH7634AS is one-chip IC that contains audio and video switches that support 21-pin SECAM and PAL connectors.
The I
2
C BUS for switch control simplifies applications, while the two expansion ports allow up to two external inputs.
•
Applications
VCRs
•
Features
1) I
2
C BUS control.
2) Video input is sync tip clamped, and includes a
small-capacity (0.022µF) input capacitor.
3) Three FSCOUT values.
4) Two expansion ports.
5) Audio mute function.
6) 75Ω driver output (pins 20 and 23) requires no
attached capacitor.
•
Absolute maximum ratings (Ta = 25°C)
Power supply voltage
Power dissipation
Operating temperature
Storage temperature
∗
Reduce by 12mW for each increase in Ta of 1°C over 25°C.
Parameter Symbol Limits Unit
V
CC 13.5 V
Pd
1200
mW
Topr – 25 ~ + 60 °C
Tstg – 55 ~ + 125 °C
•
Recommended operating conditions (Ta = 25°C)
Parameter
V
CC 8.5 13 V12
Symbol Min. Typ. Max. Unit
Operating power supply voltage
2
Multimedia ICs BH7634AS
•
Block diagram
VEDC IN
1
DRVGND
2
VTUNIN
3
DRVV
CC
4
VEXTIN
5
GND
6
ADECIN
7
FSCOUT
8
AEXTIN
9
AUXCTL1
10
ATUNIN
11
AUXCTRL2
AUXCTL2
AUXCTL2
FOR SW
I
2
C BUS
CONTROL
AUXCTL1
AUXCTL1
CURRENT
LIMITER
6.0V
REG
V
CC
VCC
12
VVTRIN
24
VEXTOUT
DRIVER
DRIVER
BUFFER
BUFFER
BUFFER
BUFFER
BUFFER
23
VVTROUT
22
VVPSOUT
21
VDECOUT
20
V
CC
19
AVTRIN
18
AEXTOUT
17
AVTROUT
16
ADECOUT
15
SCL
14
SDA
13
A
B
VSW1
A
B
C
VSW2
A
B
C
VSW3
A
B
ASW1
A
B
C
ASW2
A
B
C
ASW3
MUTE
6dB
6dB
CLAMP
CLAMP
CLAMP CLAMP
3
Multimedia ICs BH7634AS
•
Pin descriptions
Pin No.
3
4
2
1
VTUNIN
DRVV
CC
5 VEXTIN
6 GND
7 ADECIN
8 FSCOUT
9 AEXTIN
10 AUXCTL1
11 ATUNIN
12 AUXCTL2
13 SDA
14 SCL
15 ADECOUT
16 AVTROUT
17 AEXTOUT
18 AVTRIN
19 V
CC
20 VDECOUT
21 VVPSOUT
22 VVTROUT
23 VEXTOUT
24 VVTRIN
DRVGND
VDECIN
Composite video signal input (sink chip clamp).
The driver power supply. Not internally connected to V
CC (pin 19).
The driver ground. Not internally connected to the ground (pin 6).
Pin name
Composite video signal input (sink chip clamp).
Ground
Audio signal input.
Outputs one of three values (11.8V, 5.9V or 0.2V) as controlled by the I
2
C BUS.
Audio signal input.
Open collector. Normally pulled up to roughly 10k.
Audio signal output.
Open collector. Normally pulled up to roughly 10k.
I
2
C BUS Serial Data input.
I
2
C BUS Serial Clock input.
Audio output.
Audio output.
Audio output.
Audio input.
Power supply.
Composite video signal output.
Composite video signal output.
Composite video signal output.
Composite video signal output.
Composite video signal input (sink chip clamp).
Composite video signal input (sink chip clamp).
Function
4
Multimedia ICs BH7634AS
•
Pin descriptions and input output equivalent circuits
50µA
1k
50µA
1k
50k
DRVGND
GND
DRVVCC
VCC
50k
6V
12V
FS control
Three voltages are output
via I
2
C BUS control: 11.8V,
5.9V, 0.2V.
8 FSCOUT
—
™ —
Pin No.
1
3
5
24
VDECIN
VTUNIN
VEXTIN
VVTRIN
26DRVGND
GND
419DRVV
CC
VCC
7
9
11
18
ADECIN
AEXTIN
ATUNIN
AVTRIN
™ — 1.6V
—— 0V
— — 12V
™ — 5.3V
IN OUT
Pin name
Typ.
voltage
I / O equivalent circuits Pin description
Video signal input
For composite video signal
input (sink chip clamp input).
Ground
DRVGND is the driver
ground. GND is the ground
for the circuit itself. GND and
DRVGND are not connected
internally.
Power supply
DRVV
CC is the driver
power supply. V
CC is the
power supply for the circuit
itself. V
CC and DRVVCC
are not connected internally.
Audio signal input
For audio signal input.
Input impedance is 50k.
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