AK4635 datasheet(79/81 Pages) AKM

79 / 81 page

[AK4635]

Rev. 0.6

2007/10

- 79 -

1. Grounding and Power Supply Decoupling

The AK4635 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 correct

power up sequence should be observeVSS21, VSS2 and VSS3 of the AK4635 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 AK4635 as possible, with the small value

ceramic capacitor being the nearest.

2. Voltage Reference

VCOM is a signal ground of this chip. A 2.2

μF electrolytic capacitor in 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 pin in order to avoid unwanted coupling into the

AK4635.

3. Analog Inputs

The Mic and Line inputs supports single-ended and differential. The input signal range scales with nominally at 0.06 x

AVDD Vpp for the Mic input and 0.6 x AVDD Vpp for the Beep input, centered around the internal common voltage

(approx. 0.45 x AVDD). Usually the input signal is AC coupled using a capacitor. The cut-off frequency is fc = (1/2

πRC).

The AK4635 can accept input voltages from VSS1 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). Mono Line Output from the AOUT pin is centered at 0.45 x AVDD (typ).

AK4635 Datasheet(PDF) 79 Page - Asahi Kasei Microsystems