STAC9721 Datasheet, PDF (45/48 Pages) List of Unclassifed Manufacturers – Stereo AC 97 Codec With Multi-Codec Option

SigmaTel, Inc.
Data Sheet
STAC9721
Appendix A
SPLIT INDEPENDENT POWER SUPPLY OPERATION
In PC applications, one power supply input to the STAC9721/23 may be derived from a supply regulator
(as shown in Figure 3) and the other directly from the PCI power supply bus. When power is applied to
the PC, the regulated supply input to the IC will be applied some time delay after the PCI power supply.
Without proper on-chip partitioning of the analog and digital circuitry, some manufacturer's codecs would
be subject to on-chip SCR type latch-up.
SigmaTel’s STAC9721/23 specifically allows power-up sequencing delays between the analog (AVddx)
and digital (VDddx) supply pins. These two power supplies can power-up independently and at different
rates with no adverse effects to the codec. The IC is designed with independent analog and digital
circuitry that prevents on-chip SCR type latch-up.
.
3.3V or 5V ± 5%
3.3V or 5V ± 5%
0.1uF
1uF
0.1uF
0.1uF
10uF
0.1uF
25
AVdd1
38
AVdd2
1
DVdd1
12 _{PC_BEEP}
13
PHONE
14
AUX_L
15
AUX_R
16
VIDEO_L
17
VIDEO_R
18 _{CD_L}
SigmaTel
STAC9721/23
9
DVdd2
2
XTL_IN
XTL_OUT 3
SDATA_OUT ⁵
6
BIT_CLK
8
SDATA_IN
10
SYNC
11
RESET
45
CID0
46
CID1
27pF
24.576MHz
27pF
22 ohms
EMI
Filter
27pF
0.1uF
19 _{CD_GND}
20
CD_R
21
MIC1
22
MIC2
23 _{LINE_IN_L}
24 _{LINE_IN_R}
32
CAP2
1uF
27
Vref
0.1uF
1uF
28
Vrefout
31
CAP1
33
CAP3
34
APOP
47
EAPD
35
LINE_OUT_L
Optional Anti-Pop Circuit
100uF
10uF
820pF
29 _AFILT1
820pF
30
AFILT2
AVss1
26
NOTE: Pins 31, 33, 34, 40
43, 44, and 48 are No Connects
AVss2 DVss1
42 4
DVss2 LNLVL_OUT_L
7
39
36
LINE_OUT_R
37
MONO_OUT
LNLVL_OUT_R
41
** Teminate ground
plane as close to power
supply as possible
Analog Gnd
Digital Gnd
45
04/07/00
04/07/00