AK4356 Datasheet, PDF (26/29 Pages) Asahi Kasei Microsystems – 192kHz 24 Bit IX-CHANNEL DAC FOR DVD-AUDIO

ASAHI KASEI
Digital Ground
System
Controller
Analog Ground
[AK4356]
12 DVSS
13 SDTI1
14 SDTI2
15 SDTI3
16 LRCK
17 SMUTE
18 CCLK
19 CDTI
20 CSN
21 DFS0
22 CKS0
AK4356
ROUT1+ 44
ROUT1- 43
LOUT2+ 42
LOUT2- 41
ROUT2+ 40
ROUT2- 39
LOUT3+ 38
LOUT3- 37
ROUT3+ 36
ROUT3- 35
AVSS 34
Figure 9. Ground Layout
Note: AVSS and DVSS must be connected to the same analog ground plane.
1. Grounding and Power Supply Decoupling
The AK4356 requires careful attention to power supply and grounding arrangements. AVDD and DVDD are usually
supplied from analog supply in system. Alternatively if AVDD and DVDD are supplied separately, the power up sequence
is not critical. AVSS and DVSS of the AK4356 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 near to the AK4356 as possible, with the small value ceramic capacitors being the nearest.
2. Voltage Reference Inputs
VREFH sets the analog output range. VREFH pin is normally connected to AVDD with a 0.1mF ceramic capacitor. All
signals, especially clocks, should be kept away from the VREFH pin in order to avoid unwanted coupling into the AK4356.
3. Analog Outputs
The analog outputs are full-differential outputs and 0.55 x VREFH Vpp (typ) centered around the internal common voltage
(about AVDD/2). The differential outputs are summed externally, V_AOUT=(AOUT+)-(AOUT-) between AOUT+ and
AOUT-. If the summing gain is 1, the output range is 5.5Vpp (typ @VREFH=5V). The bias voltage of the external
summing circuit is supplied externally. The input data format is 2’s complement. The output voltage(V_AOUT) is a positive
full scale for 7FFFFF(@24bit) and a negative full scale for 800000H(@24bit). The ideal V_AOUT is 0V for
000000H(@24bit).
The internal switched-capacitor filter and external low pass filter attenuate the noise generated by the delta-sigma
modulator beyond the audio passband.
DC offset on AOUT+/- is eliminated without AC coupling since the analog outputs are differential. Figure 10 and 11 show
the example of external op-amp circuit summing the differential outputs.
M0072-E-01
- 26 -
1999/09