Figure 21. Ground Layout
Note: AVSS and DVSS must be connected to the same analog ground plane.
1. Grounding and Power Supply Decoupling
The AK4529 requires careful attention to power supply and grounding arrangements. AVDD and DVDD are usually
supplied from analog supply in system. Alternatively if AVDD and DVDD are supplied separately, the power up
sequence is not critical. AVSS and DVSS of the AK4529 must be connected to 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 AK4529 as possible, with the small value ceramic capacitor being
2. Voltage Reference Inputs
The voltage of VREFH sets the analog input/output range. VREFH pin is normally connected to AVDD with a 0.1µF
ceramic capacitor. VCOM is a signal ground of this chip. An electrolytic capacitor 2.2µF parallel with a 0.1µF ceramic
capacitor attached to VCOM pin eliminates the effects of high frequency noise. No load current may be drawn from
VCOM pin. All signals, especially clocks, should be kept away from the VREFH and VCOM pins in order to avoid
unwanted coupling into the AK4529.
3. Analog Inputs
ADC inputs are single-ended and internally biased to VCOM. The input signal range scales with the supply voltage and
nominally 0.62 x VREFH Vpp (typ)@fs=44.1kHz. The ADC output data format 2’s compliment. The DC offset is
removed by the internal HPF.
The AK4529 samples the analog inputs at 64fs. The digital filter rejects noise above the stop band except for multiples of
64fs. The AK4529 includes an anti-aliasing filter (RC filter) to attenuate a noise around 64fs.
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