[AK4675]
1. Grounding and Power Supply Decoupling
The AK4675 requires careful attention to power supply and grounding arrangements. AVDD, PVDD, SAVDD, DVDD,
TVDD2, TVDD3, AVDDA, PVDDA, SVDDA and TVDDA are usually supplied from the system’s analog supply.
TVDDA must be connected to DVDD. If AVDD, PVDD, SAVDD, DVDD, TVDD2, AVDDA, PVDDA and SVDDA
are supplied separately, the power-up sequence is not critical. VSS1, VSS2, VSS3, VSS4, VSS1A, VSS2A and VSS3A of
the AK4675 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 near to the AK4675 as possible, with the small value ceramic capacitor being the nearest.
2. Voltage Reference
VCOM is a signal ground of CODEC block. VCOMA is a signal ground of HP/SPK-Amp blocks. A 2.2μF electrolytic
capacitor in parallel with a 0.1μF ceramic capacitor attached to the VCOM pin eliminates the effects of high frequency
noise. A 2.2μF electrolytic capacitor in parallel with a 0.1μF ceramic capacitor attached to the VCOMA pin eliminates the
effects of high frequency noise. No load current may be drawn from the VCOM/VCOMA pins. All signals, especially
clocks, should be kept away from the VCOM and VCOMA pins in order to avoid unwanted coupling into the AK4675.
3. Analog Inputs
The Mic, Line and MIN inputs of CODEC block are single-ended. The input signal range scales with nominally at 0.6 x
AVDD Vpp (typ) at MGNL=MGNR=0dB and single-ended input, centered at the internal common voltage of CODEC
block (0.5 x AVDD). The inputs of HP/SPK-Amp blocks are single-ended. The input signal range is 2.0Vpp (typ) for
LIN1A/RIN1A pins and 1.6Vpp (typ) for SPLIN/SPRIN pins respectively, centered at the internal common voltage of
HP/SPK-Amp blocks (VCOMA=1.2V (typ)). The input signal should be AC coupled using a capacitor. The cut-off
frequency is fc = 1/ (2πRC). The AK4675 can accept input voltages from VSS1 to AVDD for CODEC block and from
VSS1A to AVDDA for HP/SPK-Amp blocks, respectively.
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). The ideal output for 0000H(@16bit) is VCOM voltage for CODEC block and
VCOMA voltage for HP/SPK-Amp blocks, respectively. VCOM voltage is 0.5 x AVDD (typ) and VCOMA voltage is
1.2Vpp (typ), respectively. The output of LOUT1/RCP, ROUT1/RCN, LOUT2S, ROUT2S, LOUT3/LOP, ROUT3/LON
pins must be AC coupled using a capacitor. The output of HPL and HPR pins must be directly connected to the headphone
without AC coupling.
MS0963-E-00
2008/05
- 176 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
