[AK4646]
1. Grounding and Power Supply Decoupling
The AK4646 requires careful attention to power supply and grounding arrangements. AVDD, DVDD and SVDD are
usually supplied from the system’s analog supply. If AVDD, DVDD and SVDD are supplied separately, the power-up
sequence is not critical. AVSS, DVSS and SVSS of the AK4646 should be connected to the analog ground plane. System
analog ground and digital ground should be connected together near to where the supplies are brought onto the printed
circuit board. Decoupling capacitors should be as near to the AK4646 as possible, with the small value ceramic capacitor
being the nearest.
2. Voltage Reference
VCOM is a signal ground of this chip. A 2.2μF electrolytic capacitor in parallel with a 0.1μF ceramic capacitor should be
attached to the VCOM pin eliminates the effects of high frequency noise. No load current may 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
AK4646.
3. Analog Inputs
The Mic, Line and MIN inputs are single-ended. The inputs signal range scales with nominally at 0.0636 x AVDD Vpp
(typ) for the Mic input and 0.636 x AVDD Vpp (typ) for the MIN input, centered around the internal common voltage (0.5
x AVDD). Usually the input signal is AC coupled using a capacitor. The cut-off frequency is fc = 1/ (2πRC). The AK4646
can accept input voltages from AVSS to AVDD.
4. Analog Outputs
The input data format for the DAC is 2’s complement. The output voltage is a positive full scale for 7FFFH (@16bit) and
a negative full scale for 8000H (@16bit). The ideal output is VCOM voltage for 0000H (@16bit). Stereo Line Output is
centered at 0.5 x AVDD (typ). The Headphone-Amp and Speaker-Amp outputs are centered at SVDD/2.
MS0557-E-05
2011/01
- 66 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
