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2010.05 - Rev.A

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Technical Note

7/8

BH3541F,BH3544F,BH3547F,BH3548F

4) GND potential

Make the GND pin voltage such that it is the lowest voltage even when operating below it. Actually confirm that the

voltage of each pin does not become a lower voltage than the GND pin, including transient phenomena.

5) Thermal design

Perform thermal design in which there are adequate margins by taking into account the allowable power dissipation in

actual states of use.

6) Shorts between pins and misinstallation

When mounting the LSI on a board, pay adequate attention to orientation and placement discrepancies of the LSI.

If it is misinstalled and the power is turned on, the LSI may be damaged. It also may be damaged if it is shorted by a

foreign substance coming between pins of the LSI or between a pin and a power supply or a pin and a GND.

7) Operation in strong magnetic fields

Adequately evaluate use in a strong magnetic field, since there is a possibility of malfunction.

8) Pop noise countermeasures

In order to prevent the pop noise that occurs when the power supply turns ON or OFF, make the rise and fall with

reference to the timing diagram shown below.

1)BH3541F/ BH3544F/ BH3548F

Fig. 16

(A):Mute period (Use as pop noise countermeasure when power supply turns ON/OFF by makingVMUTE=Lo.)

(B):Mute cancellation period (This has a time constant because it is used by the externally attached C2 and R2 as

a pop noise countermeasure on mute cancellation, so be careful of the timing.)

(C):Mute start time (As on cancellation, this has a time constant.)

2)BH3547F

Fig. 17

(A):Before VCC rise (or at the same time as VCC) make mute cancelled (VMUTE=Hi).

(B):Soft mute period (This time can be set by externally attached R2 and C2)

VCC

Vmute

OUT

SG

(Input Signal)

(Rise time)

(PLAY period)

(Fall period)

(MUTE period)

(A)

(B)

Rise time

PLAY period

Rise time

VCC

OUT

MUTE

A

B

C

A