AK4368 Datasheet, PDF (25/58 Pages) Asahi Kasei Microsystems – PLL & HP-AMP DAC

ASAHI KASEI
[AK4368]
[2] ALCϦΧόϦಈ࡞
ALCϦΧόϦಈ࡞͸ɺALCϦϛολಈ࡞ऴྃޙɺROTM1-0 bitsͰઃఆ͞Ε͚ͨ࣌ؒͩ଴ػΛߦ͍ɺ͜ͷؒɺ
DACͷೖྗϨϕϧ͕ϦΧόϦ଴ػΧ΢ϯλϦηοτϨϕϧ(−8.5dBFS)Λӽ͑Δ͜ͱ͕ͳ͚Ε͹ɺALCϦΧό
Ϧಈ࡞ΛҰճߦ͍·͢ɻ͜ͷALCϦΧόϦಈ࡞͸ɺROTM1-0 bits (Table 12)Ͱઃఆͨ࣌ؒ͠ͰθϩΫϩεݕग़
ಈ࡞Λߦ͍ͳ͕ΒɺϘϦϡʔϜ஋(L/Rڞ௨)Λઃఆ͞Εͨج४Ϩϕϧ(REF7-0 bits, Table 15)·ͰRATT bit (Table
14)Ͱઃఆ͞ΕͨεςοϓͰࣗಈతʹ૿Ճͤ͞·͢ɻ·ͨલճͷ࣌ؒ଴ػऴྃͱಉ࣌ʹ࣍ճͷ࣌ؒ଴ػΛ։࢝
͢ΔͷͰɺALCϦΧόϦಈ࡞͸ROTM1-0 bitsͰઃఆͨ͠पߦͰظΘΕ·͢ɻROTM1-0 bitsͰઃఆͨؒ͠ظத
ʹθϩΫϩεಈ࡞͕ऴྃͨ͠৔߹ɺROTM1-0 bitsͰઃఆͨ͠Ͱ·ؒظ଴ͯ͠ػɺ࣍ͷϦΧόϦಈ࡞ʹೖΓ·
͢ɻ
ALCϦΧόϦಈ࡞த·ͨ͸ϦΧόϦ଴ػதɺDACͷL/RνϟωϧͷೖྗϨϕϧ͕ͲͪΒ͔ҰํͰ΋ALCϦϛ
ολݕग़Ϩϕϧ(−6.0dBFS)Λӽ͑ͨ৔߹ɺ௚ͪʹALCϦϛολಈ࡞ʹೖΓ·͢ɻ
·ͨɺALCϦΧόϦ଴ػதʹ
(ALCϦΧόϦ଴ػΧ΢ϯλϦηοτϨϕϧ) ≤ (DACೖྗϨϕϧ) < (ALCϦϛολݕग़Ϩϕϧ)
ͱͳ͍ͬͯΔ৔߹ɺ଴ػλΠϚ͸Ϧηοτ͞Ε·͢ɻͦͷͨΊɺ
(ALCϦΧόϦ଴ػΧ΢ϯλϦηοτϨϕϧ) > (DACೖྗϨϕϧ)
ͱͳ͔ͬͨ࣌Βɺ଴ؒ࣌ػͷΧ΢ϯτ͕։࢝͞Ε·͢ɻ
·ͨɺΠϯύϧεੑͷϊΠζ͕ೖྗ͞Εͨ৔߹ɺROTM1-0 bitsͰઃఆ͞Εͨ஋ΑΓ΋ૣ͍αΠΫϧͰϦΧόϦ
ಈ࡞Λߦ͍·͢ɻ
RATT
GAIN STEP
0
1
Default
1
2
Table 14. ALCϦΧόϦήΠϯεςοϓ
REF7-0 GAIN(dB)
FFH
:
Reserved
C2H
C1H
+18.0
C0H
+17.625
BFH
+17.25
:
:
92H
+0.375
91H
0
Default
90H
−0.375
:
:
73H
−11.25
72H
−11.625
71H
−12.0
70H
:
Reserved
00H
Table 15. ALCϦΧόϦಈ࡞࣌ͷج४஋ͷઃఆ
MS0409-J-01
- 25 -
2005/08