AK4709 Datasheet, PDF (19/42 Pages) Asahi Kasei Microsystems – Low Power AV SCART Switch

[AK4709]
■ Volume Control #1 (Main Volume)
The AK4709 has main volume control (Volume #1) as shown in Table 8.
(02H: D5-D0)
L5
L4
L3
L2
L1
L0
1
0
0
0
1
0
1
0
0
0
0
1
1
0
0
0
0
0
0
1
1
1
1
1
…
…
…
…
…
…
0
0
0
0
0
1
0
0
0
0
0
0
Note: The output must not exceed 2.15Vrms.
Table 8. Volume #1
Gain
+6dB
+4dB
+2dB
0dB
…
-60dB
Mute
(default)
When the MOD bit = “1”(default), changing volume levels does not cause pop noise. MDT1-0 bits select the transition
time (Table 9). When the new gain value 1EH(-2dB) is written to gain resistor while the actual (stable) gain is 1FH(0dB),
the gain changes to 1EH(-2dB) within the transition time selected by MDT1-0 bits. The built-in volume controller
compares the actual gain to the value of gain register after finishing the transition time, and re-changes the actual gain to
new resister value within the transition time if the register value is different from the actual gain when compared. When
the MOD bit = “0” then there is no transition time and the gain changes immediately. This change may cause a click noise.
WR
[Gain=1EH]
WR
[Gain=1DH]
WR
[Gain=1CH]
Gain Register
Actual Gain
1FH
1EH
compare
1FH (to 1EH)
1EH
1DH
1CH
compare compare
(to 1DH) (to 1CH)
1CH
1DH
Transition Time (5.3ms to 42.7ms pop free.)
Figure 6. Volume Change Operation (MOD bit = “1”)
MDT1
0
0
1
1
MDT0
Transition Time
0
5.3ms
1
10.7ms
0
21.3ms
1
42.7ms
Table 9. Volume Transition Time (typ.)
(default)
MS1319-E-00
- 19 -
2011/07