AK4642VN Datasheet, PDF (37/82 Pages) Asahi Kasei Microsystems – 16-Bit ΔΣ Stereo CODEC with MIC/HP/SPK-AMP

ASAHI KASEI
[AK4642]
2. ALCϦΧόϦಈ࡞
ALCϦΧόϦಈ࡞͸ɺWTM1-0Ͱઃఆ͞Εͨ࣌ؒ(Table 24)଴ػΛߦ͍ɺ͜ͷؒɺग़ྗ৴߸͕ALCϦΧόϦ଴
ػΧ΢ϯλϦηοτϨϕϧ(Table 21)Λӽ͢͜ͱ͕ͳ͚Ε͹ALCϦΧόϦಈ࡞Λߦ͍·͢ɻ͜ͷALCϦΧόϦ
ಈ࡞͸ઃఆ͞Εͨج४Ϩϕϧ(Table 26) ·ͰZTM1-0Ͱઃఆͨ࣌ؒ͠(Table 23)ͰθϩΫϩεݕग़ಈ࡞Λߦ͍
ͳ͕ΒɺRGAIN1-0 bitͰઃఆͨ͠஋(Table 25)͚ͩIVL, IVR஋(L/Rڞ௨)Λࣗಈతʹ૿Ճͤ͞·͢ɻ͜ͷALCϦ
ΧόϦಈ࡞͸WTM1-0Ͱઃఆͨ͠पߦͰظΘΕ·͢ɻ
ྫ͑͹ɺࡏݱͷIVL, IVR஋͕30Hͷ৔߹ɺRGAIN1-0 bit = “01”(2 steps)ʹઃఆ͓ͯ͘͠ͱɺALCϦΧόϦಈ࡞
ʹΑͬͯIVL, IVR஋͸32Hʹมߋ͞Εɺ0.75dB(0.375dB x 2)૿Ճ͞Ε·͢ɻIVL, IVR஋͕ج४Ϩϕϧ (REF7-0)
ʹୡͨ͠৔߹ɺIVL, IVR஋ͷ૿Ճ͸ߦ͍·ͤΜɻ
·ͨɺALCϦΧόϦ଴ػதʹ
(ϦΧόϦ଴ػΧ΢ϯλϦηοτϨϕϧ) ≤ Output Signal < (Ϧϛολݕग़Ϩϕϧ)
ͱͳ͍ͬͯΔ৔߹ɺ଴ػλΠϚ͸Ϧηοτ͞Ε·͢ɻͦͷͨΊɺ
(ϦΧόϦ଴ػΧ΢ϯλϦηοτϨϕϧ) > Output Signal
ͱͳ͔ͬͨ࣌Βɺ଴ؒ࣌ػͷΧ΢ϯτ͕։࢝͞Ε·͢ɻ
·ͨɺALCಈ࡞͸ΠϯύϧεੑͷϊΠζʹ΋ରԠͨ͠ALCʹͳ͍ͬͯ·͢ɻΠϯύϧεੑͷϊΠζ͕ೖྗ͞
Εͨ৔߹ɺ௨ৗͷϦΧόϦಈ࡞ΑΓ΋ૣ͍αΠΫϧͰϦΧόϦಈ࡞Λߦ͍·͢ɻྫ͑͹ɺϚΠΫϩϑΥϯʹ
ॠؒతʹେ͖ͳԻ͕ೖྗ͞Εͨ৔߹ɺ͜ͷಈ࡞ʹΑΓେ͖ͳԻʹຒ΋Εͨখ৴߸Λվળ͢Δ͜ͱ͕Ͱ͖·
͢ɻ
WTM1
0
0
1
1
WTM0
0
1
0
1
ALCϦΧόϦपظ
8kHz
16kHz
44.1kHz
128/fs
16ms
8ms
2.9ms
256/fs
32ms
16ms
5.8ms
512/fs
64ms
32ms
11.6ms
1024/fs
128ms
64ms
23.2ms
Table 24. ALCϦΧόϦ଴ؒ࣌ػͷઃఆ
Default
RGAIN1 RGAIN0
GAIN STEP
0
0
1 step
0.375dB
0
1
2 step
0.750dB
1
0
3 step
1.125dB
1
1
4 step
1.500dB
Table 25. ALC ϦΧόϦήΠϯྔͷઃఆ
Default
REF7-0
GAIN(dB)
Step
F1H
+36.0
F0H
+35.625
EFH
+35.25
:
:
E2H
+30.375
E1H
+30.0
0.375dB Default
E0H
+29.625
:
:
03H
−53.25
02H
−53.625
01H
−54.0
00H
MUTE
Table 26. ALCϦΧόϦಈ࡞࣌ͷج४஋ઃఆ
MS0358-J-02
- 37 -
2005/04