AK4388 Datasheet, PDF (14/18 Pages) Asahi Kasei Microsystems – 192kHz 24-Bit 2ch ΔΣ DAC

ASAHI KASEI
[AK4388]
1. Grounding and Power Supply Decoupling
VDD and VSS are supplied from analog supply and should be separated from system digital supply. Decoupling
capacitor, especially 0.1µF ceramic capacitor for high frequency should be placed as near to VDD as possible. The
differential Voltage between VDD and VSS pins set the analog output range.
2. Analog Outputs
The analog outputs are single-ended and centered around the VCOM voltage. The output signal range is typically
3.20Vpp (typ@VDD=5V). The internal switched-capacitor filter and continuous-time filter attenuate the noise generated
by the delta-sigma modulator beyond the audio passband. The output voltage is a positive full scale for 7FFFFFH
(@24bit) and a negative full scale for 800000H (@24bit). The ideal output is VCOM voltage for 000000H (@24bit).
DC offsets on analog outputs are eliminated by AC coupling since analog outputs have DC offsets of VCOM + a few mV.
Figure 8 shows an example of the external LPF with 3.20Vpp (1.13Vrms) output. Figure 9 shows an example of the
external LPF with 2Vrms output.
AK4388
AOUT
10u
220
22k
Analog
Out
3.2Vpp (1.13Vrms)
2.2nF
fc=328.8kHz, g=-0.064dB at 40kHz
Figure 8. External 1^st order LPF Circuit Example (simple)
AK4388
10u
2.7k
AOUT
22k
390p
3.9k
3.3k
+Vop
3.9k
390p
-Vop
Analog
Out
5.93Vpp (2.09Vrms)
fc=125.8kHz, Q=0.752, g=0.058dB at 40kHz
Figure 9. External 2^nd order LPF Circuit Example (using op-amp with dual power supplies)
MS0485-E-01
- 14 -
2006/07