SM6453AB_02 Datasheet, PDF (12/19 Pages) Nippon Precision Circuits Inc – 3-wire Serial Data Volume Control for Headphone Amplifier IC

SM6453AB
System Reset Function (RSTN)
The system is reset using a LOW-level pulse on RSTN. After the system is reset, AGC is OFF, bass boost mode
is BB1, input selector is LIN1/RIN1, and LOUT/ROUT output voltage gain is muted.
AGC
Bass boost mode Bass boost function
Input Select
EVR gain (G_EVR)
Output gain (G_O)
OFF
BB1
OFF
LIN1, RIN1
MUTE
MUTE
Bass Boost Function with Automatic Gain Control (AGC)
Equivalent circuit
Rch 1
Rch 2
Lch 1
Lch 2
*2
CINR1
1µF
RIN1
*2
CINR2
1µF
RIN2
*2
CINL1
1µF
LIN1
*2
CINL2
1µF
LIN2
EVR
Block
RIN
(Equivalent input
resistance:23kΩ)
VREF1
EVR
Block
RIN
(Equivalent input
resistance:23kΩ)
VREF1
Bass Boost Block
R1 *3
R1R
40kΩ
BSTN
C2
2200pF
R3 _*4
R1L
2kΩ
40kΩ
BSTC
Bass
Boost
Amp
VREF1
VREF1 VREF1
240kΩ
60kΩ
60kΩ
Headphone
Amp
VREF1
240kΩ
60kΩ
60kΩ
Headphone
Amp
VREF1
VDD
COUT
220µF
COUT
220µF
LRMXO
AGC Block
AGC Amp
VREF1
VREF1 VREF1
*1: From “Measurement circuit”. Adjustment AGC detection level and time constant.
*2: C_INR1 = C_INL1, C_INR2 = C_INL2 → C_IN
*3: RIN1 = LIN1 → R₁ = (R_1R/2 + R_1L/2) = 20kΩ
*4: BB1 → R₃ = 15kΩ, BB2 → R₃ = 60kΩ
NIPPON PRECISION CIRCUITS INC.—12