AK4695 Datasheet, PDF (97/107 Pages) Asahi Kasei Microsystems – 24bit 4ch CODEC with MIC/HP/SPK/LINE-AMP

[AK4695]
1. Grounding and Power Supply Decoupling
The AK4695 requires careful attention to power supply and grounding arrangements. AVDD and SVDD are usually
supplied from the system’s analog supply, and DVDD and TVDD are supplied from the system’s digital power supply. If
AVDD, DVDD, TVDD and SVDD are supplied separately, the power-up sequence is not critical. The PDN pin should be
held “L” when power supplies are tuning on. The PDN pin is allowed to be “H” after all power supplies are applied and
settled.
To avoid pop noise on headphone output and line output when power up/down, the AK4695 should be operated along the
following recommended power-up/down sequence.
1) Power-up
- The PDN pin should be held “L” when power supplies are turning on. The AK4695 can be reset by keeping the PDN
pin “L” for 1.5μs or longer after all power supplies are applied and settled.
2) Power-down
- Each of power supplies can be powered OFF after the PDN pin is set to “L”.
VSS1, VSS2 and VSS3 of the AK4695 should be connected to the analog ground plane. System analog ground and digital
ground should be wired separately and connected together as close as possible to where the supplies are brought onto the
printed circuit board. Decoupling capacitors should be as close the power supply pins as possible. Especially, the small
value ceramic capacitor is to be closest.
2. Voltage Reference
VCOM is a signal ground of this chip. A 1μF ceramic capacitor connected to the VCOM pin eliminates the effects of high
frequency noise. It should be connected as close as possible to the VCOM pin. No load current is allowed to be drawn from
the VCOM pin. All signals, especially clocks, should be kept away from the VCOM pin in order to avoid unwanted
coupling into the AK4695.
3. Charge Pump
2.2μF±50% capacitors between the CP and CN pins, and the VEE and VSS3 pins should be low ESR ceramic capacitors.
These capacitors must be connected as close as possible to the pins. No load current may be drawn from the VEE pin.
4. Analog Inputs
The MIC input is single-ended. The input signal range scales with typ. (0.566 x AVDD) Vpp (@ MGAIN = +3dB),
centered around the internal common voltage (typ. (0.5 x AVDD) V). Usually the input signal is AC coupled using a
capacitor (1μF or less is recommended). The cut-off frequency is fc = 1/(2RC). Connect a 1nF capacitor between each
analog input and VSS1 for stabilized characteristics.
5. Analog Outputs
The stereo line output A is centered on typ. (0.5 x AVDD) V. They (LOUTA/ROUTA pins) must be AC-coupled using a
capacitor. The headphone output is single-ended and centered around VSS (0V). There is no need for AC coupling
capacitors. The speaker outputs (SPP/SPN pins) are centered on SVDD/2 (typ.), and they should be connected directly to
a speaker. There is no need for AC coupling capacitors. The stereo line outputs B (LOUTB/ROUTB pins) are centered on
typ. (0.5 x AVDD) V. These pins must be AC-coupled using a capacitor.
MS1463-E-01
- 97 -
2014/12