AK4953A Datasheet, PDF (79/96 Pages) Asahi Kasei Microsystems – 24bit Stereo CODEC with MIC/HP/SPK-AMP

[AK4953A]
1. Grounding and Power Supply Decoupling
The AK4953A requires careful attention to power supply and grounding arrangements. If AVDD, DVDD, TVDD and
SVDD are supplied separately, the power-up sequence is not critical. VSS1, VSS2, VSS3 and VSS4 of the AK4953A
must be connected to the analog ground plane. System analog ground and digital ground must be connected together near
to where the supplies are brought onto the printed circuit board. Decoupling capacitors must be as near to the AK4953A
as possible, with the small value ceramic capacitor being the nearest.
2. Internal Regulated Voltage Power Supply
The input voltage to the REGFIL pin is used as power supply (typ. 2.5V) for the internal analog circuit. A 2.2μF±50%
electrolytic capacitor connected between the REGFIL and VSS1 pins eliminates the effects of high frequency noise. This
capacitor in particular should be connected as close as possible to the pin. No load current may be drawn from the
REGFIL pin. All digital signals, especially clocks, should be kept away from the REGFIL pin in order to avoid unwanted
coupling into the AK4953A.
3. Voltage Reference
VCOM is a signal ground of this chip (typ. 1.25V). A 2.2μF±50% electrolytic capacitor connected between this pin and
the VSS1 pin eliminates the effects of high frequency noise. This capacitor in particular should be connected as close as
possible to the pin. No load current may be drawn from the VCOM pin. All digital signals, especially clocks, must be kept
away from the VCOM pin in order to avoid unwanted coupling into the AK4953A.
4. Charge Pump
2.2μF±50% capacitors between the CP and CN pins, and the PVEE 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
PVEE pin.
5. Analog Inputs
The MIC input is single-ended. The input signal range scales with nominally at typ. 2.4Vpp (@ MGAIN = 0dB), centered
around the internal signal ground (typ. 1.25V). Usually the input signal is AC coupled using a capacitor (1μF or less is
recommended). The cut-off frequency is fc = 1/ (2πRC). The AK4953A can accept input voltages from VSS1 to AVDD.
6. Analog Outputs
The input data format for the DAC is 2’s complement. The output voltage is a positive full scale for 7FFFFFH (@24bit)
and a negative full scale for 800000H (@24bit). The ideal output is VCOM voltage for 000000H (@24bit). The
headphone output is single-ended and centered around VSS (0V). There is no need for AC coupling capacitors. The
speaker outputs are centered on 0.5 x SVDD (typ).
MS1252-E-00
- 79 -
2010/10