lv49157v Sanyo Semiconductor Corporation, lv49157v Datasheet - Page 18

• Manufacturer Part Number: lv49157v
• Description: Bi-cmos Lsi Class-d Audio Power Amplifier With Built-in Headphone Ampifier Btl 15w ? 2ch
• Manufacturer: Sanyo Semiconductor Corporation

Cut-off frequency calculation method and the output LC filter setting
The cut off frequency fc of the output LC filter is calculated by the following formula.
Also, by setting the cut off frequency fc, the value of C L and L is calculated by using the following formula.
In general, the value from 20% to 30% of C L is set to C.
In case of fc = 30kHz
Above formula is common calculation method and is a measure of constant setting.
In fact, it is necessary to set with each set that considers the speaker characteristics.
In addition, please set the fixed number to become Q ≤ 1 in currents in the fc neighborhood increasing if Q value of the LC
filter is big.
R L [Ω]
16
4
6
8
fc =
C L =
L =
OUT +
OUT -
√2 × R L
2π√2LC L
4π fc
2√2 × π R L fc
L [μH]
15
22
33
68
1
1
L
L
C
C
C L [μF]
0.68
0.47
0.22
1
C L
R L
C [μF]
0.047
0.22
0.15
0.1
LV49157V
0.650
0.636
0.704
0.739
Q
No.A1567-18/30