AK4637EN Datasheet, PDF (41/96 Pages) Asahi Kasei Microsystems – 24bit Mono CODEC with MIC/SPK-AMP

[AK4637]
■ Digital Microphone
1. Connection to Digital Microphones
When DMIC bit is set to “1”, the AIN/IN+ and BEEP/IN- pins become DMDAT (digital microphone data
input) and DMCLK (digital microphone clock supply) pins, respectively. The same voltage as AVDD must
be provided to the digital microphone. The Figure 36 shows mono connection examples. The DMCLK
clock is input to a digital microphone from the AK4637. The digital microphone outputs 1bit data, which is
generated by Modulator using DMCLK clock, to the DMDAT pin. PMDM bit control power up/down of
the digital block (Decimation Filter and Digital Filter). (PMADC bit 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 AK4637 is powered down (PDN pin= “L”), the DMCLK and DMDAT pins become floating
state. Pull-down resistors must be connected to DMCLK and DMDAT pins externally to avoid this floating
state. When the digital microphone is used, AVDD must be provided as 2.8~3.6V.
AVDD （2.8V~3.6V）
AK4637
VDD
AMP



Modulator
DMCLK(64fs)
100kΩ
DMDAT
R
PLL
Decimation _HPF1
Filter
Programmable
Filter
ALC
Figure 36. Connection Example of Monaural Digital Microphone
MCKI
SDTO
015010680-E-00
- 41 -
2015/09