BU9253AS Datasheet, PDF (6/6 Pages) Rohm – KARAOKE echo IC

Multimedia ICs
(3) Setting the echo loop gain
VIN
LPF
R
+
AD
R
R: R = 1: 1
mix
Recommendable gain
– 6dB
BU9253AS / BU9253FS / BU9255FS
OdB
SRAM
VIN
9
+
VO
8
OUT
VDLY
DA
7
2
Recommendable gain
+ 3dB
VR
Echo loop
ATT
VIN ~ VDLY···A =
VDLY
VIN
(A < 1)
∗ With Pin NO. BU9253FS
Fig. 3
With VOMax being the maximum amplitude of VO at this
time (when the phases, including that of the DLY cir-
cuit, are in alignment):
∞
VOMax. = (1 + A + A2 + ···) VIN = Σ
K=0
A^K · VIN = ¹ VIN
1-A
Thus, maximum allowable input is the value of VOMax
provided the specifications (1 = A). Assuming a feed-
back ratio (A) of 0.7 and a maximum VOUT of 4.0 VP-P,
VIN must be less than 1.2 VP-P.
•^{External dimensions (Units: mm)}
BU9253FS / BU9255FS
BU9253AS
6.6 ± 0.2
16
9
1
8
0.8
0.36 ± 0.1 0.3Min.
0.15
SSOP-A16
6
19.4 ± 0.3
18
10
1
9
7.62
1.778
0.5 ± 0.1
0° ~ 15°
0.3 ± 0.1
SDIP18