µPD63310

13

2.3 Analog Output Block

The analog audio output pins (OUTL and OUTR) and the DAC output pins (DACL and DACR) are internally biased to

1.4 V (TYP.), so an output coupling capacitor should be inserted to cut the DC component (see Figure 2-3).

The out-of-band component of the output signals from these analog pins is attenuated by a post filter (LPF) in the IC,

so there is no need for an external LPF.

Set the load resistance to at least 20 k

Ω (the speakers cannot be directly driven, so insert a power amp IC before the

speaker).

Analog audio output pins and DAC output pins that are not used can be left unconnected.

Figure 2-3. Analog Output Block Connection Example

OUTL etc.

+

µ

4.7 F

33 k

Ω

2.4 Use Cautions

When changing the volume (addresses 17 and 18) between the DAC output and the output mixer, noise (“pop noise”)

may be output from an analog audio output pins (OUTL or OUTR). Such noise is due to the output offset voltage of an

on-chip DAC.

If this noise is audible enough to be a problem, take the following measures.

(1) Set mute mode for the volume (addresses 17 and 18) between the DAC output and the output mixer.

(2) Connect the DAC output pins (DACL and DALR) via a capacitor to a pair of unused analog input pins

(such as IN4L and IN4R).

(3) Adjust the volume (such as addresses 15 and 16) between the analog input pins connected as described

in (2) above and the output mixer to adjust the DAC output volume.