[AK4675]
When PMSPL and PMSPR bits are set to “0”, the speaker block (ALC + Speaker-Amp) can be powered-down
completely. In case of OSCN bit = “0”, the power-up/down time is 30ms (typ.) and 48ms (max.). In case of OSCN bit =
“1”, the power-up/down time depends on MSEL bit setting and MCKIA frequency (Table 90).
MSEL bit
0
MCKIA Freq
Power-Up Time
2.048MHz
2.8224MHz
3.072MHz
19.5ms (40000/MCKIA)
21.5ms (60000/MCKIA)
19.5ms (60000/MCKIA)
1
Table 90. Class D SPK-Amp Power-Up Time (OSC bit = “1”)
In case of OSCN bit = “0”, the write operation to SPGA5-0 bits is prohibited during 1.6ms after PMSPL or PMSPR bit is
set to “1”. In case of OSCN bit = “1”, the write operation to SPGA5-0 bits is prohibited during the power-up time of the
speaker volume block (Table 91) after PMSPL or PMSPR bit is set to “1”.
MSEL bit
0
MCKIA Freq
Power-Up Time
2.048MHz
2.8224MHz
3.072MHz
1ms (2048/MCKIA)
1.1ms (3072/MCKIA)
1ms (3072/MCKIA)
1
Table 91. Write Operation Prohibited Time of Speaker Volume after Power-up (OSCN bit = “1”)
PMSP bits
Speaker-Amp
0
1
Power-down & Hi-Z
Power-up & Output
(default)
Table 92. Speaker-Amp Output State
■ Thermal Shutdown Function
When the internal device temperature rises up irregularly (e.g. output pins of speaker amplifier are shortened), the charge
pump circuit, headphone amplifier and speaker amplifier are automatically powered-down and then THDET bit becomes
“1”. The powered-down charge pump circuit, headphone amplifier and speaker amplifier do not return to normal
operation unless HP/SPK-Amp blocks of the AK4675 are reset by the PDNA pin “L”. The device status can be monitored
by THDET bit.
■ HP/SPK-Amp Operation Clock
The AK4675 includes built-in clock oscillator for the internal operation of Class-D Speaker-Amp and Charge Pump
circuit. The AK4675 supports both internal oscillator mode and external clock mode (MCKIA pin). MSEL bit selects the
clock frequency for the MCKIA pin.
OSCN bit
Operation Clock
Internal OSC
External Clock (MCKIA pin)
0
1
(default)
Table 93. Internal Oscillator / External Clock select
MSEL bit
MCKIA Frequency
2.048MHz
2.8224MHz or 3.072MHz
0
1
(default)
Table 94. MCKIA Input Frequency Select
MS0963-E-00
2008/05
- 118 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
