
ASAHI KASEI
[AK4520A]
0163-E-00
1997/3
- 9 -
OPERATION OVERVIEW
System Clock Input
The AK4520A with CMODE is used to select either MCLK=256fs or 384fs. The relationship between the
external clock applied to the MCLK input and the desired sample rate is defined in Table 1 . The LRCK clock
input must be synchronized with MCLK, however the phase is not critical. Internal timing is synchronized to
LRCK upon power-up or when the internal timing becomes out of phase. All external clocks must be present
unless both PWDA and PWAD ="L", otherwise excessive current may result from abnormal operation of
internal dynamic logic.
 MCLK
 256fs
 CMODE="L"
  8.1920MHz
 11.2896MHz
 12.2880MHz
 SCLK
 64fs
 fs
 384fs
 CMODE="H"
 12.2880MHz
 16.9344MHz
 18.4320MHz
Table 1 . System Clock Example
 32fs
 32.0kHz
 44.1kHz
 48.0kHz
 2.048MHz
 2.822MHz
 3.072MHz
 1.0240MHz
 1.4112MHz
 1.5360MHz
Audio Serial Interface Format
Data is shifted in/out the SDTI/SDTO pins using SCLK and LRCK inputs. Four serial data modes are
supported selected by the DIF0 and DIF1 pins as shown in Table 2 . In all modes the serial data is MSB-first,
2's compliment format is clocked on the falling edge of SCLK. For mode 3, if SCLK is 32fs, then the least
significant bits will be truncated.
Mode
DIF1
DIF0
SDTO(ADC)
SDTI(DAC)
L/R
SCLK
0
0
0
 20bit, MSB justified
 16bit, LSB justified
 H/L
≥
32fs
1
0
1
 20bit, MSB justified
 20bit, LSB justified
 H/L
≥
40fs
2
1
0
 20bit, MSB justified
 20bit, MSB justifie
 H/L
≥
40fs
3
1
1
 IIS(I2S)
 IIS(I2S)
 L/H
 32fs or
≥
40fs
Table 2 . Serial Data Modes