BD3870FS ROHM Co. Ltd., BD3870FS Datasheet - Page 14

• Manufacturer Part Number: BD3870FS
• Description: Audio Sound Processor For Home Audio
• Manufacturer: ROHM Co. Ltd.

●Cautions on use
1.
2.
3.
4.
5.
6.
7.
8.
9.
10. Switching between functions
11. Input coupling capacitor
Numbers and data in entries are representative design values and are not guaranteed values of the items.
Although ROHM is confident that the example application circuit reflects the best possible recommendations, be sure to
verify circuit characteristics for your particular application. Modification of constants for other externally connected circuits
may cause variations in both static and transient characteristics for external components as well as this Rohm IC. Allow
for sufficient margins when determining circuit constants.
Absolute maximum ratings
GND potential
Thermal design
Short circuit between terminals and erroneous mounting
Operation in strong electromagnetic field
Power-ON RESET
2-wire serial control
Use of the IC in excess of absolute maximum ratings, such as the applied voltage or operating temperature range
(Topr), may result in IC damage. Assumptions should not be made regarding the state of the IC (short mode or open
mode) when such damage is suffered. A physical safety measure, such as a fuse, should be implemented when using
the IC at times where the absolute maximum ratings may be exceeded.
Ensure a minimum GND pin potential in all operating conditions. Make sure that no pins are at a voltage below the
GND at any time, regardless of whether it is a transient signal or not.
Perform thermal design, in which there are adequate margins, by taking into account the permissible dissipation (Pd)
in actual states of use.
Pay attention to the assembly direction of the ICs. Wrong mounting direction or shorts between terminals, GND, or other
components on the circuits, can damage the IC.
Using the ICs in a strong electromagnetic field can cause operation malfunction.
A built-in circuit for performing initialization inside the IC at power-ON is provided. In unstable systems it is
recommended that the data shall be sent to all the addresses during power-ON, until this operation cycle is
completed. Mute should be applied during this cycle.
For the CL and DA terminals, the patterned and other wirings should be routed as not to cause interference with the
analog-signal-related lines.
Shock sound is absorbed when switching between the volume, bass, and treble functions.
As described in the figure below, low frequency characteristics are determined depending on the external
capacitor value for input coupling, and the input impedance value inside the IC.
C
Loud Speaker Equalizer
(BD3872FS only)
Input Selector
Fig.23
Treble Gain
Input Gain
Bass Gain
Surround
Function
Volume
R
14/16
Initial Condition
Input A
-∞dB
OFF
OFF
0dB
0dB
0dB
A (f)
A (f) =
G
0
1+(2π fCR)
(2π fCR)
Fig.24
2
2
f