[AK4679]
■ Digital MIC
1. Connection to Digital MIC
The AK4679 can be connected to digital microphone by setting DMIC bit = “1”. When DMIC bit is set to “1”, the LIN1
and RIN1 pins become DMDAT (digital microphone data input) and DMCLK (digital microphone clock supply) pins
respectively. The same power supply as AVDD must be provided to the digital microphone. The Figure 57 and Figure 58
show mono/stereo connection examples. The DMCLK signal is output from the AK4679, and the digital microphone
outputs 1bit data, which generated by ΔΣModulator, from DMDAT. PMDML/R bits control power up/down of the digital
block (Decimation Filter and HPF1). PMADL/PMADR bits settings do not affect the digital microphone power
management. The DCLKE bit controls ON/OFF of the output clock from the DMCLK pin. When the AK4679 is powered
down (PDNA pin= “L”), the DMCLK and DMDAT pins are pulled-down by internal 2.7kΩ(typ.) resistor. However,
when the AK4679 is powered-up (PDNA pin = “H”), path of the internal pulled-down resistor is OFF. Therefore, external
pull-down resistor(R) should be connected to the DMDAT pin to avoid floating state.
AVDD
AK4679
VDD
MCKI
DMCLK(64fs)
PLL
ΔΣ
AMP
Modulator
SDTO
Programmable
Filter
Decimation
Filter
DMDAT
R
HPF1
ALC
Lch
VDD
ΔΣ
Modulator
AMP
Rch
Figure 57. Connection Example of Stereo Digital MIC
AVDD
AK4679
VDD
MCKI
DMCLK(64fs)
PLL
ΔΣ
AMP
Modulator
SDTO
Programmable
Filter
Decimation
Filter
DMDAT
R
HPF1
ALC
Figure 58. Connection Example of Mono Digital MIC
MS1402-E-06
2013/02
- 64 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
