AK5700VN AKM [Asahi Kasei Microsystems], AK5700VN Datasheet - Page 34

• Manufacturer Part Number: AK5700VN
• Description: 16-Bit ?? Mono ADC with PLL & MIC-AMP
• Manufacturer: AKM [Asahi Kasei Microsystems]

ASAHI KASEI
The ALC (Automatic Level Control) is done by ALC block when ALC bit is “1”.
1. ALC Limiter Operation
During the ALC limiter operation, when the output exceeds the ALC limiter detection level (Table 22), the IVL value is
attenuated automatically by the amount defined by the ALC limiter ATT step (Table 23).
When ZELMN bit = “0” (zero cross detection is enabled), the IVL value is changed by ALC limiter operation at the
individual zero crossing point of zero crossing timeout. ZTM1-0 bits set the zero crossing timeout period of both ALC
limiter and recovery operation (Table 24).
When ZELMN bit = “1” (zero cross detection is disabled), IVL value is immediately (period: 1/fs) changed by ALC
limiter operation. Attenuation step is fixed to 1 step regardless as the setting of LMAT1-0 bits.
The attenuation operation is done continuously until the input signal level becomes ALC limiter detection level (Table 22)
or less. After completing the attenuation operation, unless ALC bit is changed to “0”, the operation repeats when the input
signal level exceeds LMTH1-0 bits.
MS0569-E-01
ALC Operation
LMTH1
0
0
1
1
ZTM1
LMTH0
0
0
1
1
0
1
0
1
ZELMN
Table 22. ALC Limiter Detection Level / Recovery Counter Reset Level
0
1
ZTM0
ALC Limier Detection Level
0
1
0
1
ALC Output ≥ −2.5dBFS
ALC Output ≥ −4.1dBFS
ALC Output ≥ −6.0dBFS
ALC Output ≥ −8.5dBFS
LMAT1
Table 24. ALC Zero Crossing Timeout Period
0
0
1
1
x
1024/fs
128/fs
256/fs
512/fs
Table 23. ALC Limiter ATT Step
LMAT0
0
1
0
1
x
128ms
8kHz
16ms
32ms
64ms
- 34 -
Zero Crossing Timeout Period
ALC Recovery Waiting Counter Reset Level
−2.5dBFS > ALC Output ≥ −4.1dBFS
−4.1dBFS > ALC Output ≥ −6.0dBFS
−6.0dBFS > ALC Output ≥ −8.5dBFS
ALC Limiter ATT Step
−8.5dBFS > ALC Output ≥ −12dBFS
1 step
2 step
4 step
8 step
1step
16kHz
16ms
32ms
64ms
8ms
0.375dB
0.750dB
1.500dB
3.000dB
0.375dB
44.1kHz
11.6ms
23.2ms
2.9ms
5.8ms
Default
Default
Default
[AK5700]
2006/12