ROHM BH7802K Datasheet
1
Video ICs
Single chip Hi-Fi audio signal
processor
BH7802K
The BH7802K incorporates the functions for a VHS audio signal processing system on a single chip. The circuits on
the chip are a peak-noise reduction processor (PNR), an FM modulator / demodulator circuit, an I / O switcher, an
automatic FM detector circuit, an FM bandpass filter, and a regulator circuit.
•
Applications
VCR
S
•
Features
1) Operates off dual ± power supply which allows a
large reduction in the number of coupling capacitors
required. A built-in regulator makes it easy to construct a power supply system.
2) A two-line I
2
C bus control decoder circuit is provided, allowing the various IC modes to be set using
serial control.
3) A four line input switcher is included (tuner, BS, and
line 1 / 2). The output switcher can switch between
STEREO, LEFT, and RIGHT, and Hi-Fi, MIX, and
NORMAL, and a BS MONITOR function is also provided. The MIX AMP is AV-LINK compatible.
4) The PNR processor and FM modulator / demodulator circuit have reversed characteristics at recording
and playback. In addition, the adjustment for carrrier
frequency and FM deviation / playback level are
common.
5) The built-in bandpass filter excels at attenuation of
other channels, and can be directly coupled to the
playback amplifier. The FM recording output block
has a high-performance low-pass filter to produce
sine wave output.
6) Slope-control-type FM-switching-noise compensation circuit.
7) Envelope detector circuit and noise-detector-type
automatic FM detector circuit.
8) VCO that uses the color signal sub-carrier frequency
fsc (NTSC: 3.579545MHz, PAL: 4.433619MHz) and
auto-adjusting BPF circuit ensure stable adjustment
with no fluctuation due to mounting stress or time.
•
Absolute maximum ratings (Ta = 25°C)
Parameter
Applied voltage
Storage temperature
V
CC
VEE
VIN
Tstg
18, 36pin······························
6.0
39pin·································
– 6.0
5, 6, 32pin····························
6.5
Pins other than the above····
6.0
– 55 ~ + 125
V
Symbol Limits Unit
V
V
VIN V
Power dissipation Pd
850
∗
mW
Operating temperature Topr – 10 ~ + 70 °C
°C
∗
Reduced by 8.5mW for each increase in Ta of 1°C over 25°C, when mounted on a 70mm × 70mm, t = 1.6mm glass epoxy board.
2
Video ICs BH7802K
•
Block diagram
33 32 31 30 29 28 27 26 25 24 23
1
INPUT
SWITCH
MIX
AMP
PNR
ENVE
LOPE
Hi-Fi
DET
MODEM
ALC
DATA
DECODER
MODEM
FMBPF
VCO BPF
AUTO
ADJUST
D.O.
COM.
FM
OUT
SW
2 3
REG
4 5 6 7 8 9 10 11
TUNER R IN
TUNER L IN
TUNER M IN
Hi-Fi ALC
SCL
SDA
GNDD
FSC IN
NR TC L
WTNG L
NR EMPH L
LINE2 R IN
MUTE CTRL
NORMAL OUT
LINE L OUT
LINE R OUT
MIX OUT
MIX ALC
NORMAL IN
NR TC R
WTNG R
NR EMPH R
DC FB R
FM REC OUT
AUDIO HEAD SW
PULSE IN
FM ALC
VCCM
VCO FO ADJ
BPF ADJ
GNDM
ENVE OUT / ADJ FLAG
/ Hi-Fi DET
FM PB IN
DC FB L
LINE2 L IN
VREFP
V
CC
ERP
GND
V
EE
LINE1 R IN
LINE1 L IN
ERM
BS R IN
BS L IN
34
35
36
37
38
39
40
41
42
43
44
22
21
20
18
17
16
15
14
13
12
LINE2L
LINE2R
BSL
BSR
LINE
AMP
LINE
AMP
OUTPUT
SWITCH
PNR
19
3
Video ICs BH7802K
•
Pin descriptions
Pin No. Pin name I / O circuitPin voltageFunction
2, 1, 3 TUNER IN L, R, M 150kΩ0.0VTuner input (L, R, M)
4 Hi-Fi ALC EF (NPN) ~ 200Ω0.0VALC time constant setting for Hi-Fi audio
5SCL B (PNP)—CLOCK input for I2C bus control
6SDA B (PNP)—
——
DATA input for I2C bus control
7 GNDD GND for serial control
8 FSC IN 200kΩ0.0V
9, 25 NR TC L, R —
—
—
– 5.0V
fSC input for VCO and BPF adjustment
12, 22 DC FB L, R 11.5kΩ0.0VPNR operating reference potential point
15 GNDM —0.0VGND for PNR, MODEM and BPF
16 BPF f0 ADJ EF (NPN) ~ 200Ω1.9VCenter frequency adjustment for FM BPF
17 VCO f0 ADJ EF (NPN)2.5VVCO control current setting
18 VCCM —5.0VVCC for MODEM and BPF
19 FM ALC EF (NPN) ~ 2.5kΩ0.0VFM ALC time constant setting
20 AHSWP IN B (PNP)—Audio head switching pulse input
26 NORMAL IN 100kΩ0.0VNormal input
28 MIX OUT EF (NPN)0.0VMixer amplifier output for RF converter
30, 29 LINE L, R OUT 330Ω0.0VLine output
31 NORMAL OUT EF (P-P)0.0VNormal output
32 MUTE CTRL 3kΩ ( > 2.5V)—Line output mute control input
34, 33 LINE2 L, R IN 88kΩ0.0VLINE2 input (L, R)
36 VCC —5.0VVCC regulator
37 ERP C (NPN)5.0VVCC regulator error output
38 GND —0.0VI / O switch GND
39 VEE — – 5.0VVEE regulator
41, 40 LINE1 IN L, R 88kΩ0.0VLINE1 input (L, R)
42 ERM C (PNP) – 5.0VVEE regulator error output
44, 43 BS IN L, R 88kΩ0.0VBS input (L, R)
PNR attack and recovery time setting.
Attack R: 530Ω, Recovery R: 6.5kΩ
10, 24 WTNG L, R 0.0V
Waiting characteristic, treble time constant
(External C = 0.022µF)
11, 23 NR EMPH L, R 0.0V
NR emphasis time constant setting
(External C = 0.0047µF)
13 FM PB IN 100kΩ0.0V
Playback FM input 660mV
P-P Typ.
Input coupling capacito (GND ~ V
CC)
21 FM REC OUT EF (NPN) ~ 200ΩEE: 3.3V
EE: recording FM output , sine wave output
PB: FM BPF output monitor
27 MIX ALC EF (NPN) ~ 500Ω – 5.0V
ALC time constant setting for mixer amplifier.
Attack and recovery time setting
35 VREFP 10kΩ2.5V
V
CC / 2 reference voltage
(power on detect and pre-charge functions)
14 / ADJ FLAG
/ Hi-Fi DET
ENVE OUT
EE: 50kΩEE: 0.8V
PB, ADJ: EF (NPN)PB: 1.0V
FM Lch signal component envelope output
/ Hi-Fi DET output / ADJ FLAG output for ADJ
∗
I / O circuit; EF: emitter follower, P-P: push pull, B: base, and C: collector.
All numerical values are standardized values.
4
Video ICs BH7802K
•
Input / output circuits
TUNER L / R / M IN (2, 1, 3pin) LINE1, LINE2, BS L / R IN (34, 33, 41, 40, 44, 43pin)
LINE L / R OUT (30, 29pin) MIX OUT (28pin)
FM REC OUT (21pin) FM PB IN (13pin)
VCC
VEE
GND
1
3k
(2, 3pin)
– 2.0V
2.0V
150k
VCC
VEE
GND
25k 330
30
(29pin)
11.56k
VCC
VEE
GND
33
58k
(34, 40, 41,
43, 44pin)
– 2.0V
2.0V
30k
50
50
VCC
VEE
GND
200
21
8k
200
VCC
VEE
GND
200
5k
47k
200
28
3p
VCC
VEE
GND
2k50k
13
12.5k
3.5V
100k
20p
PB
5
Video ICs BH7802K
AHSWP IN (20pin) ENVE OUT / ADJ FLAG / Hi-Fi DET (14pin)
SCL (5pin) SDA (6pin)
MUTE CTRL (32pin) FSC IN (8pin)
VCC
VEE
GND
20
5k
VCC
VEE
GND
14
50k
200
42.5k 30k
PB
VCC
VEE
5
30k
3V
VCC
VEE
GND
32
GND
VCC
VEE
GND
2k
50k100k
100k
50k16k
200
10k
2.5V
51k
10k 2k
VCC
VEE
6
30k
90
3V
8
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