AK4440 Datasheet, PDF (17/31 Pages) Asahi Kasei Microsystems – 192kHz 24-Bit 8ch DAC with 2Vrms Output

[AK4440]
■ Analog Output Block
The internal negative power supply generation circuit (Figure 16) provides a negative power supply for the internal
2Vrms amplifier. It allows the AK4440 to output an audio signal centered at VSS (0V, typ) as shown in Figure 17. The
negative power generation circuit (Figure 16) needs 1.0μF low ESR (Equivalent Series Resistance) capacitors (Ca, Cb).
If this capacitor is polarized, the positive polarity pin should be connected to the CP and VSS2 pins. This circuit
operates by clocks generated from MCLK. When MCLK stops, the AK4440 is placed in the reset mode automatically
and the analog outputs settle to VSS (0V, typ).
AK4440
VDD
Charge
Pump
Negative Power
CP
CN VSS2
VEE
Cb
(+)
1u F
1uF Ca
(+)
Figure 16. Negative Power Generation Circuit
AK4440
0V
LOUT
(ROUT)
2.12 Vrms
Figure 17. Audio Signal Output
■ De-emphasis Filter
A digital de-emphasis filter is available for 32, 44.1 or 48kHz sampling rates (tc = 50/15μs). For double speed and quad
speed modes, the digital de-emphasis filter is always off. In serial control mode, the DEM1-0 bits are valid for the DAC
enabled by the DEMA-D bits (Table 9). In parallel control mode, DEM1-0 pins are valid (Table 10).
DEM1 bit
0
0
1
1
DEM0 bit
0
1
0
1
Mode
44.1kHz
OFF
48kHz
32kHz
(default)
Table 9 De-emphasis Filter Control in Serial Control Mode (Normal Speed Mode)
MS1088-E-01
- 17 -
2011/03