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AK4688EN Datasheet, PDF (33/36 Pages) Asahi Kasei Microsystems – Asynchronous Stereo CODEC with Capless Line I/O | |||
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[AK4688]
1. άϥϯÏ
ͱిݯͷÏΧοÏϦϯά
é»æºã¨ã°ã©ã³ãã®åãæ¹ã«ã¯åå注æãã¦ä¸ãããé常ãAVDD1, AVDD2, DVDDã«ã¯ã·ã¹ãã ã®ã¢ããã°é»
æºã®æ ¹å
ããåãã¦é»æºãä¾çµ¦ãã¦ãã ãããAVDD1, AVDD2, DVDDãå¥é»æºã§ä¾çµ¦ãããå ´åã«ã¯ãé»æº
ç«ã¡ä¸ãã·ã¼ã±ã³ã¹ãèããå¿
è¦ã¯ããã¾ãããAVSS1, AVSS2, DVSS ã¯åãã¢ããã°ã°ã©ã³ãï¼ãã¿ã°ã©
ã³ãï¼ã«æ¥ç¶ãã¦ä¸ãããã·ã¹ãã ã®ã°ã©ã³ãã¯ã¢ããã°ã¨ãã£ã¸ã¿ã«ã§åãã¦é
ç·ãPCãã¼ãä¸ã®é»æºã«
è¿ãã¨ããã§æ¥ç¶ãã¦ä¸ãããå°å®¹éã®ãã«ãããªã³ã°ã³ã³ãã³ãµã¯ãªãã¹ãé»æºãã³ã®è¿ãã«æ¥ç¶ãã¦ä¸
ããã
2. ج४ిѹ
AVDD1ã¨AVSS1ã®é»å§å·®ãã¢ããã°å
¥åã¬ã³ã¸ãè¨å®ãã¾ããAVDD2ã¨AVSS2ã®é»å§å·®ãã¢ããã°åºåã¬
ã³ã¸ãè¨å®ãã¾ããVREFã¯ã¢ããã°ä¿¡å·ã®åºæºé»å§ã¨ãã¦ä½¿ããã¾ãããã®ãã³ã«ã¯é«å¨æ³¢ãã¤ãºãé¤å»ã
ãããã«1μFã®ã»ã©ããã¯ã³ã³ãã³ãµãAVSS1/AVSS2ã¨ã®éã«æ¥ç¶ãã¦ä¸ãããVERF pinããé»æµãåã£ã¦
ã¯ããã¾ããããã£ã¸ã¿ã«ä¿¡å·ãç¹ã«ã¯ããã¯ã¯å¤èª¿å¨ã¸ã®ã«ãããªã³ã°ãé¿ãããããVREF pinããã§ã
ãã ãé¢ãã¦ä¸ããã
3. ÎÏϩάà³à¾
AK4688ã¸ã®ã¢ããã°å
¥åã¯ãå¤ä»ãã®æµæãä»ãã¦Pre-Ampã«ã·ã³ã°ã«ã¨ã³ãã§å
¥åããã¾ããå
¥åä¿¡å·ã¬
ã³ã¸ã«å¯¾ãã¦ãPre-AmpåºåãADC(LO, RO pin)ã®å
¥åã¬ã³ã¸(typ. 1.91Vrms)ã«ãªãããã«Feedbackæµæã調ç¯
ãã¦ä¸ãããåºåã³ã¼ãã®ãã©ã¼ããã㯠2âsã³ã³ããªã¡ã³ãã§ããDCãªãã»ãã(ADCèªä½ã®DCãªãã»ã
ããå«ã)ã¯å
èµã®HPFã§ãã£ã³ã»ã«ããã¾ããAK4688ã¯64fsã§ã¢ããã°å
¥åããµã³ããªã³ã°ãã¾ãããã£ã¸
ã¿ã«ãã£ã«ã¿ã¯ã64fsã®æ´æ°åä»è¿ã®å¸¯åãé¤ãé»æ¢å以ä¸ã®ãã¤ãºãå
¨ã¦é¤å»ãã¾ããAK4688ã¯64fsä»è¿
ã®ãã¤ãºãæ¸è¡°ãããããã«ã¢ã³ãã¨ãªã¢ã¸ã³ã°ãã£ã«ã¿(RCãã£ã«ã¿)ãå
èµãã¦ãã¾ãã
4. ÎÏϩάà¥à¾
ã¢ããã°åºåã¯ã·ã³ã°ã«ã¨ã³ãã«ãªã£ã¦ãããåºåã¬ã³ã¸ã¯AVSS2(0V,typ)ãä¸å¿ã« 2.0Vrms(typ,
@AVDD2=3.3V) ã§ããå
èµã® ÎΣ å¤èª¿å¨ãçºçãã帯åå¤ãã¤ãº (ã·ã§ã¼ãã³ã°ãã¤ãº) ã¯å
èµã®ã¹ã¤ããã
ãã£ãã·ã¿ãã£ã«ã¿ (SCF) ã¨é£ç¶ãã£ã«ã¿ (CTF) ã§æ¸è¡°ããã¾ãã帯åå¤ãã¤ãºãåé¡ã«ãªãå ´åã¯ãç°¡å
ãª1次ã®LPF(Figure 23)ãå
¥ãã¦ä¸ããã
å
¥åã³ã¼ãã®ãã©ã¼ããã㯠2âs complement (2 ã®è£æ°) ã§7FFFFFH(@24bit) ã«å¯¾ãã¦ã¯æ£ã®ãã«ã¹ã±ã¼ã«ã
800000H(@24bit) ã«å¯¾ãã¦ã¯è² ã®ãã«ã¹ã±ã¼ã«ã000000H(@24bit) ã§ã®VL/ROUTã®çæ³å¤ã¯ 0V(VSS)ãåºåãã
ã¾ããDCãªãã»ããã¯Â±5ï½V以ä¸ã§ãã
AK4688
L/ROUT
470
Analog
Out
2.0Vrms (typ)
2.2nF
(fc = 154kHz, gain = -0.28dB @ 40kHz, -1.04dB @ 80kHz)
Figure 23. External 1st order LPF Circuit Example
5. جàµà´àª¢à§Í·à®«Ò
LIN, RIN pinã¯Pre-Ampã®ãµãã³ã°ãã¼ãã§ããä»ã®ä¿¡å·ã¨ã®ã«ãããªã³ã°ã«ã¯åå注æããå
¥åæµæã¾ã§ã®
é
ç·ãã§ããã ãçããªãããã«ãã¦ä¸ãããLI, RI pinãåæ§ã«ä»ã®ä¿¡å·ã¨ã®ã«ãããªã³ã°ã¨Feedbackæµæ
ã¾ã§ã®é
ç·é·ã«æ³¨æãã¦ä¸ãããã¾ããLIN, RIN pinã®ä¸ã§å
¥åã¨ãã¦ä½¿ç¨ãããªããã³ãããå ´åã¯ãªã¼ã
ã³ã«ãã¦ä¸ããã
MS1420-J-00
- 33 -
2012/05
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