ak4538 AKM Semiconductor, Inc., ak4538 Datasheet - Page 30

• Manufacturer Part Number: ak4538
• Description: 16bit ?? Codec With Mic/hp/spk-amp
• Manufacturer: AKM Semiconductor, Inc.

ASAHI KASEI
n Digital Attenuator
The AK4538 has a channel-independent digital attenuator (256 levels, 0.5dB step, Mute). The attenuation level of each
channel can be set by the ATTL/R7-0 bits (Table 21). When the DATTC bit = “1”, the ATTL7-0 bits control both Lch and
Rch attenuation levels. When the DATTC bit = “0”, the ATTL7-0 bits control Lch level and ATTR7-0 bits control Rch
level. This attenuator has a soft transition function. It takes 1061/fs from 00H to FFH.
n Soft Mute
Soft mute operation is performed in the digital domain. When the SMUTE bit goes to a “1”, the output signal is attenuated
by - (“0”) during the cycle set by the TM1-0 bits. When the SMUTE bit is returned to “0”, the mute is cancelled and the
output attenuation gradually changes to 0dB during the cycle set of the TM1-0 bits. If the soft mute is cancelled within the
cycle set by the TM1-0 bits after starting the operation, the attenuation is discontinued and returned to 0dB. The soft mute
is effective for changing the signal source without stopping the signal transmission.
The soft mute function is independent of output volume and cascade connected between both functions.
NOTE:
(1) The output signal is attenuated until - (“0”) by the cycle set by the TM1-0 bits.
(2) Analog output corresponding to digital input has the group delay (GD).
(3) If the soft mute is cancelled within the cycle of setting the TM1-0 bits, the attenuation is discounted and returned to
MS0198-E-01
0dB(the set value).
SMUTE bit
Attenuation
Analog Output
0dB
-
T M 1-0 bit
ATTL/R7-0
(1)
FDH
FEH
FFH
00H
01H
02H
03H
:
:
Figure 23. Soft Mute Function
Table 21. DATT Code Table
G D
MUTE (
Attenuation
- 30 -
(2)
126.5dB
127.0dB
0.5dB
1.0dB
1.5dB
0dB
:
:
)
T M 1-0 bit
Default
G D
(3)
[AK4538]
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