[AK4675]
■ Class-D Speaker-Amp
The output signal from ALC block is converted by PWM and is outputted from the SPP/SPN pins by BLT. The signal of
ALC block is input from the SPIN pin. A 0.1uF capacitor should be connected between the LOUT3 (ROUT3) pin and the
SPIN pin in order to cancel DC offset of Line Out circuit.
LOUT3 (ROUT3) SPIN pin
SPGA5-0bits
typ.26kΩ
0.1μF
Line Out
-
+
ALCA
AK4675
Figure 85. Example of normal connection for Speaker (fc = 66Hz @ -3dB)
When the input signal level is 0.56Vrms, the speaker-amp outputs 0.6W. The internal default gain is +11.76dB.
The SPK-Amp outputs 0.6W(/1ch) when 0.56Vrm mono signal is input at single-end mode and ALC = OFF
(SPGA=0dB).
When ALCA = ON (ALCA bit= “1”), ALCA outputs -7.5dBV ~ -9.5dBV if LMTHA bit = “0”, and outputs -11.5dBV ~
-13.5dBV if LMTHA bit = “1”. REFA5-0 bits set the reference level. The internal gain of the class-D speaker amplifier is
fixed to +11.76dB.
ALCA
Class-D
SPIN
ALCA OFF: SPGA5-0bit
ON: REF5-0bit
(+11.76dB)
Figure 86. Speaker-Amp Path Level Diagram
MS0963-E-00
2008/05
- 117 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
