AK4649 Datasheet, PDF (35/96 Pages) Asahi Kasei Microsystems – 24bit Stereo CODEC with MIC/SPK-AMP

[AK4649]
■ MIC Power
When PMMP bit = “1”and MPDMP bit = “0”, the MPWR pin supplies power for the microphone. This output voltage is
typically 0.8 x AVDD and the load resistance is minimum 0.5kΩ. In case of using two sets of stereo microphone, the load
resistance is minimum 2kΩ for each channel. Any capacitor must not be connected directly to the MPWR pin (Figure 24).
PMMP bit
MPWR pin
0
Hi-Z
(default)
1
Output
Table 22. MIC Power (MPDMP bit = “0”)
MIC Power
MPWR pin
LIN1 pin
RIN1 pin
LIN2 pin
RIN2 pin
Figure 24. MIC Block Circuit
Microphone
Microphone
Microphone
Microphone
■ Digital MIC
1. Connection to Digital MIC
The AK4649 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. By setting MPDMP bit = “1”, the MPWR pin becomes DMP (digital microphone power supply) pin and can
supply the power to the digital microphone (max. 4mA). When DMPE bit = “0”, the same power supply as AVDD must
be provided to the digital microphone. The Figure 25 and Figure 26 show mono/stereo connection examples. The
DMCLK signal is output from the AK4649, 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 Digital
Filter). 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 AK4649 is powered down (PDN pin= “L”), the DMCLK
and DMDAT pin are floating state. Pull-down resistors must be connected to the DMCLK and DMDAT pin externally to
avoid floating state.
MS1023-E-01
- 35 -
2010/08