ak4648 AKM Semiconductor, Inc., ak4648 Datasheet - Page 77

• Manufacturer Part Number: ak4648
• Description: Stereo Codec With Mic/hp/spk-amp
• Manufacturer: AKM Semiconductor, Inc.

Note 64. The output level is calculated assuming that output signal is not clipped. In actual case, output signal may be
<ALC Operation Example of Speaker Playback>
MS0625-E-01
AVDD
clipped when DAC outputs 0dBFS signal. DAC output level should be set to lower level by setting digital
volume so that Speaker-Amp output level is 5.2Vpp (HVDD=3.6V) or 7.0Vpp (HVDD=4.5V) or less and output
signal is not clipped.
3.3V
Register Name
LMTH1-0
ZELMN
ZTM1-0
WTM2-0
REF7-0
IVL7-0,
IVR7-0
LMAT1-0
RGAIN1-0
ALC
HVDD
3.6V
4.5V
Table 67. ALC Opeation Example of Speaker Playback
SPKG2-0 bits
Comment
Limiter detection Level
Limiter zero crossing detection
Zero crossing timeout period
Recovery waiting period
*WTM2-0 bits should be the same data
Maximum gain at recovery operation
Gain of IVOL
Limiter ATT step
Recovery GAIN step
ALC enable
as ZTM1-0 bits
000
001
010
011
000
001
010
011
Table 66. SPK-Amp Output Level
5.2Vpp (Note 64)
5.2Vpp (Note 64)
7.0Vpp (Note 64)
ALC bit = “0”
- 77 -
3.30Vpp
3.30Vpp
4.15Vpp
6.75Vpp
4.15Vpp
SPK-Amp Output (DAC Input = 0dBFS)
(LMTH1-0 bits = “00”; -2.5dBFS)
Data
C1H
91H
011
00
10
00
00
0
1
fs=44.1kHz
5.2Vpp (Note 64)
5.2Vpp (Note 64)
7.0Vpp (Note 64)
ALC bit = “1”
− 2.5dBFS
Operation
3.11Vpp
3.92Vpp
3.11Vpp
3.92Vpp
6.37Vpp
23.2ms
11.6ms
Enable
+18dB
Enable
1 step
1 step
0dB
[AK4648]
2007/06