LV3311PNM Datasheet, PDF (18/20 Pages) Sanyo Semicon Device – Bi-CMOS LSI For Car Audio Systems Electronic Volume IC

LV3311PNM
Usage Cautions
(1) Data Transmission at power on
• The status of internal analog switches is unstable at power on. Therefore, perform muting or some other
countermeasure until the data has been set.
• At power on, initial setting data must be sent once in order to stabilize the bias of each block in a short time.
(2) Description of zero cross switching circuit operation
The LV3311PNM have a function to switch zero cross comparator signal detection locations, enabling the selection
of the optimum detection location for blocks whose data is to be updated.Basically, the switching noise can be
minimized by inputting the signal immediately following the block whose data is to be updated to the zero cross
comparator, so it is necessary to switch the detection location every time.
Input gain
Volume
Fader
Switch
Zero cross
comparator
LV3311PNM zero cross detection circuit
(3) Zero Cross Switching Control method
The zero cross switching control method consists of setting the zero cross control bits to the zero cross detection mode,
and specifying the detection blocks before transmitting the data. These control bits are latched immediately following
data transfer, that is to say beforehand in sync with the falling edge of CE, so when updating data of volumes, etc., it
is possible to perform mode setting and zero cross switching with one data transfer.
(4) Zero cross timer setting
If the input signal becomes lower than the zero cross comparator detection sensitivity, or if only low-frequency
signals are input, zero cross detection continues to be impossible, and data is not latched during this time. The zero
cross timer can set a time for forcible latch during such a status when zero cross detection is not possible.
(5) Soft step operation
The LV3311PNM have a soft step function at 3 band equalizer block and subwoofer block for low switching noise.
The Soft step time can be selected by send to CCB control. (l0ms, 20ms, 40ms, 80ms)
A soft step function can be implemented by set to soft step on. (Set to minimum step)
CE "H" → "L"
soft step start
soft step time
No.A0720-18/20