1
Video ICs
Single chip Hi-Fi audio signal
processor
BH7801BK
The BH7801BK 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.
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 con-
struct a power supply system.
2) A two-line I
2
C BUS control decoder circuit is provid-
ed, 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
STREO, LEFT, and RIGHT, and Hi-Fi, MIX, and
NORMAL, and a BS MONITOR function is also pro-
vided.
4) The PNR processor and FM modulator / demodula-
tor circuit have reversed characteristics at recording
and playback. In addition, the adjustment for carrier
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 compensa-
tion 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.
•
Features
•
Applications
VCRs
•
Absolute maximum ratings (Ta = 25°C)
Parameter
Applied voltage
Storage temperature
VCC
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.