ak4552 AKM Semiconductor, Inc., ak4552 Datasheet - Page 13

• Manufacturer Part Number: ak4552
• Description: 3v 96khz 24bit ?? Codec
• Manufacturer: AKM Semiconductor, Inc.

ASAHI KASEI
[AK4552]
1. Grounding and Power Supply Decoupling
The AK4552 requires careful attention to power supply and grounding arrangements. VA and VD are usually supplied
from analog supply in system. Alternatively if VA and VD are supplied separately, the power up sequence is not critical.
VSS of the AK4552 should 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 AK4552 as possible, with the small value ceramic capacitor being the nearest.
2. Voltage Reference
The input to VA voltage sets the analog input/output range. A 0.1 F ceramic capacitor and a 10 F electrolytic capacitor is
connected to VA and VSS pins, normally. VCOM is a signal ground of this chip. An electrolytic less than 1 F (typ; max:
2.2 F) in parallel with a 0.1 F ceramic capacitor attached to these pins eliminates the effects of high frequency noise. No
load current may be drawn from VCOM pin. All signals, especially clock, should be kept away from the VA, VD and
VCOM pins in order to avoid unwanted coupling into the AK4552.
3. Analog Inputs
ADC inputs are single-ended and internally biased to VCOM. The input signal range scales with the supply voltage and
nominally 0.617 x VA Vpp (typ). The ADC output data format 2’s compliment. The output code is 7FFFFFH(@24bit) for
input above a positive full scale and 800000H(@24bit) for input below a negative full scale. The ideal code is
000000H(@24bit) with no input signal.
The AK4552 samples the analog inputs at 64fs. The digital filter rejects noise above the stop band except for multiples of
64fs. A simple RC filter may be used to attenuate any noise around 64fs and most audio signals do not have significant
energy at 64fs.
4. Analog Outputs
The analog outputs are also single-ended and centered around the VCOM voltage. The input signal range scales with the
supply voltage and nominally 0.583 x VA Vpp (typ). The DAC input data format is 2’s compliment. 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). If the noise generated by the delta-sigma modulator beyond the audio band would be the
problem, the attenuation by external filter is required.
DC offsets on analog outputs are eliminated by AC coupling since DAC outputs have DC offsets of a few mV.
MS0055-E-01
2001/02
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