ASAHI KASEI

[AK5384]

MS0225-E-00

2003/05

- 18 -

1. Grounding and Power Supply Decoupling

The AK5384 requires careful attention to power supply and grounding arrangements. AVDD and DVDD are usually

supplied from the analog supply in the system. Alternatively if AVDD and DVDD are supplied separately, the power up

sequence is not critical. AVSS and DVSS of the AK5384 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 AK5384 as possible, with the small value ceramic capacitor being

the closest.

2. Voltage Reference Inputs

The differential voltage between AVDD and AVSS sets the analog input range. VCOM is a signal ground of this chip. An

electrolytic capacitor 2.2

µF 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 the VCOM pin. All signals, especially clocks, should be kept away

from the VCOM pin in order to avoid unwanted coupling into the AK5384.

3. Analog Inputs

The AK5384 accepts +5V supply voltage. Any voltage which exceeds the upper limit of AVDD+0.3V and lower limit of

AVSS

−0.3V and any current beyond 10mA for the analog input pins (LIN+/−, RIN+/−) should be avoided. Excessive

currents to the input pins may damage the device. Hence input pins must be protected from signals at or beyond these

limits. Use caution specially in case of using

±15V in other analog circuits.

The analog inputs are differential and internally biased to the common voltage (AVDD/2) with 26k

Ω(typ). The input signal

range between LIN(RIN)+ and LIN(RIN)

− scales with the supply voltage and nominally ±0.58 x AVDD. The AK5384 can

accept input voltages from AVSS to AVDD. The ADC output data format 2’s compliment. The internal HPF removes the

DC offset.

The AK5384 samples the analog inputs at 64fs. The digital filter rejects noise above the stop band except for multiples of

64fs.