AK4648 Datasheet, PDF (33/119 Pages) Asahi Kasei Microsystems – Stereo CODEC with MIC/HP/SPK-AMP

[AK4648]
When PLL reference clock input is LRCK or BICK pin, the sampling frequency is selected by FS3 and FS1-0 bits. (Table
7). FS2 bit is “don’t care”.
Mode FS3 bit FS2 bit FS1 bit FS0 bit Sampling Frequency Range
0
0
x
0
0
7.35kHz ≤ fs ≤ 8kHz (default)
1
0
x
0
1
8kHz < fs ≤ 12kHz
2
0
x
1
0
12kHz < fs ≤ 16kHz
3
0
x
1
1
16kHz < fs ≤ 24kHz
6
1
x
1
0
24kHz < fs ≤ 32kHz
7
1
x
1
1
32kHz < fs ≤ 48kHz
Others
Others
N/A
(x: Don’t care)
Table 7. Setting of Sampling Frequency at PMPLL bit = “1” (Reference Clock = LRCK or BICK pin)
■ PLL Unlock State
1) PLL Master Mode (AIN3 bit = “0”; PMPLL bit = “1”, M/S bit = “1”)
In this mode, LRCK and BICK pins go to “L” and irregular frequency clock is output from MCKO pins at MCKO bit is
“1” before the PLL goes to lock state after PMPLL bit = “0” Æ “1”. If MCKO bit is “0”, MCKO pin goes to “L” (Table
8).
After the PLL is locked, the first period of LRCK and BICK may be invalid clock, but these clocks return to normal state
after a period of 1/fs.
When sampling frequency is changed, BICK and LRCK pins do not output irregular frequency clocks but go to “L” by
setting PMPLL bit to “0”.
PLL State
After that PMPLL bit “0” Æ “1”
MCKO pin
MCKO bit = “0” MCKO bit = “1”
“L” Output
Invalid
BICK pin
“L” Output
PLL Unlock (except case above) “L” Output
Invalid
Invalid
PLL Lock
“L” Output
Table 10
Table 11
Table 8. Clock Operation at PLL Master Mode (PMPLL bit = “1”, M/S bit = “1”)
LRCK pin
“L” Output
Invalid
1fs Output
2) PLL Slave Mode (AIN3 bit = “0”, PMPLL bit = “1”, M/S bit = “0”)
In this mode, an invalid clock is output from MCKO pin before the PLL goes to lock state after PMPLL bit = “0” Æ “1”.
Then, the clock selected by Table 10 is output from MCKO pin when PLL is locked. ADC and DAC output invalid data
when the PLL is unlocked. For DAC, the output signal should be muted by writing “0” to DACL and DACH bits.
PLL State
Just after PMPLL bit “0” Æ “1”
MCKO pin
MCKO bit = “0” MCKO bit = “1”
“L” Output
Invalid
PLL Unlock (except case above)
“L” Output
Invalid
PLL Lock
“L” Output
Output
Table 9. Clock Operation at PLL Slave Mode (PMPLL bit = “0”, M/S bit = “0”)
MS0625-E-01
- 33 -
2007/06