ak5367a AKM Semiconductor, Inc., ak5367a Datasheet - Page 26

• Manufacturer Part Number: ak5367a
• Description: 96khz 24-bit ?? Adc With 0v Bias Selector
• Manufacturer: AKM Semiconductor, Inc.

1. Grounding and Power Supply Decoupling
The AK5367A requires careful attention to power supply and grounding arrangements. AVDD, DVDD and CVDD are
usually supplied from the analog supply in the system. Alternatively if AVDD, DVDD and CVDD are supplied
separately, the power up sequence is not critical. VSS1 and VSS2 of the AK5367A must be connected to 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 AK5367A as possible, with the small
value ceramic capacitor being the closest.
2. Voltage Reference Inputs
The differential voltage between AVDD and VSS1 sets the analog input range. VCOM is a signal common of this chip.
An electrolytic capacitor 2.2µF parallel with a 0.1µF ceramic capacitor 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 pins in order to avoid unwanted coupling into the AK5367A.
3. Analog Inputs
An analog input of AK5367A is single-ended input to Pre-Amp through the external resistor. For input signal range,
adjust feedback resistor so that Pre-Amp output may become the input range (typ. 0.6 x AVDD Vpp) of ADC
(LISEL,RISEL pin). Between the Pre-Amp output (LOUT, ROUT pin) and the ADC input (LISEL,RISEL pin) is AC
coupled with capacitor. When the impedance of LISEL/RISEL pins is “R” and the capacitor of between the Pre-Amp
output and the ADC input is “C”, the cut-off frequency is fc = 1/(2πRC). The ADC output data format is 2’s compliment.
The internal HPF removes the DC offset. The AK5367A samples the analog inputs at 64fs. The digital filter rejects noise
above the stop band except for multiples of 64fs. The AK5367A includes an anti-aliasing filter (RC filter) to attenuate a
noise around 64fs.
4. Attention to the PCB Wiring
LIN1-4 and RIN1-4 pins are the summing nodes of the Pre-Amp. Attention should be given to avoid coupling with other
signals on those nodes. This can be accomplished by making the wire length of the input resistors as short as possible. The
same theory also applies to the LOPIN/ROPIN pins and feedback resistors; keep the wire length to a minimum. Unused
input pins among LIN1-4 and RIN1-4 pins should be left open. When external devices are connected to LOUT and ROUT
pin, the input impedance is min. 15kΩ.
4. I
SCL and SDA pins should be connected to DVDD through the resistor based on I
between each pin and DVDD, the pulled up voltage must be DVDD or
MS0967-E-00
2
C bus Connection
SDA pin
+3.3V
Figure 25. SDA pin output
- 26 -
DVDD
VSS2
AK5367A
lower(Figure
2
C standard. As there is a protection
25).
[AK5367A]
2008/05