Audio ICs
Serial sound control IC
BH3854AS / BH3854AFS
The BH3854AS and BH3854AFS are signal processing ICs designed for volume and tone control in CD radio cassettes
and other audio products. Their three-line serial control enables them to control volume and tone on the basis of signals
from a microcomputer, etc.
FApplications
CD radio cassettes, mini component stereo systems, car
stereos
FFeatures
1) They facilitate direct serial control from a microcom-
puter of volume (main volume) and tone (bass,
treble). DC control is also possible.
2) Volume is produced by a low-distortion, low-noise
VCA. Designed to minimize step noise.
3) Input amp can be used for gain adjustment, and ma-
trix surround yields powerful sound.
4) Stable standard voltage supply and built-in I / O buff-
er mean that few attachments are needed. SSOP32
package designed to save space.
FAbsolute
maximum ratings (Ta = 25_C)
5) Open collector has four outputs, which makes logic
control possible.
6) Excellent for volume and tone control devices in CD
radio cassettes, micro components, car stereos,
televisions, etc.
7) Digital GND pin and analog GND pin are separated
with an impedence of more than 1MΩ.
FRecommended
operating conditions (Ta = 25_C)
633
Audio ICs
FBlock
diagram
BH3854AS / BH3854AFS
FPin
descriptions
634
Audio ICs
BH3854AS / BH3854AFS
FElectrical
characteristics (unless otherwise noted, Ta = 25_C, V
CC
= 8V, f = 1kHz, BW = 20
X
20kHz,
VOL = Max., TONE = ALL FLAT, Rg = 600Ω, R
L
= 10kΩ, INPUT AMP GAIN = 0dB)
FTiming
chart constants
Note: About the output pins...
SPins
1 through 4 (pins 12 through 15) are reset when the power is turned ON.
SAfter
the pins are reset, until the Vcc voltage setting for this IC (BH3854) is reached and the next data
Sis
input, the pins only operate while the CK, DATA, and LATCH lines are all maintained at LOW.
SBe
sure that no more than 9V is applied to any of the output pins.
635
Audio ICs
FMeasurement
circuit
BH3854AS / BH3854AFS
636
Audio ICs
FOperation
of measuring circuit switches
BH3854AS / BH3854AFS
637
