ak4368 AKM Semiconductor, Inc., ak4368 Datasheet - Page 58

• Manufacturer Part Number: ak4368
• Description: Dac With Built-in Pll & Hp-amp
• Manufacturer: AKM Semiconductor, Inc.

ASAHI KASEI
[AK4368EG]
1. Grounding and Power Supply Decoupling
The AK4368 requires careful attention to power supply and grounding arrangements. AVDD, PVDD and HVDD are
usually supplied from the analog power supply in the system and DVDD is supplied from AVDD via a 10Ω resistor.
Alternatively if AVDD and DVDD are supplied separately, the power up sequence is not critical. When AVDD and
HVDD are supplied separately, AVDD is powered-up at the same time or earlier than HVDD. When the AK4368 is
powered-down, HVDD is powered-down at the same time or later than AVDD. The power up sequence of PVDD is not
critical. AVSS, DVSS, PVSS and HVSS must 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 close to the AK4368 as possible, with the small value ceramic capacitors being the nearest.
2. Voltage Reference
The input voltage to AVDD sets the analog output range. A 0.1µF ceramic capacitor and a 10µF electrolytic capacitor are
connected between AVDD and AVSS. VCOM is a signal ground of this chip (0.475 x AVDD). An electrolytic 2.2µF
attached between VCOM and AVSS 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 AVDD and VCOM in order to avoid unwanted
coupling into the AK4368.
3. Analog Outputs
The analog outputs are single-ended outputs, and 0.47 x AVDD Vpp(typ)@-3dBFS for headphone-amp and 0.61xAVDD
Vpp(typ) @0dBFS for LOUT/ROUT centered on the VCOM voltage. The input data format is 2’s compliment. The
output voltage is a positive full scale for 7FFFFFH(@24bit) and negative full scale for 800000H(@24bit). The ideal
output is VCOM voltage for 000000H(@24bit).
DC offsets on the analog outputs is eliminated by AC coupling since the analog outputs have a DC offset equal to VCOM
plus a few mV.
MS0529-E-00
2006/07
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