STAC9758 Datasheet, PDF (19/119 Pages) Integrated Device Technology – HIGH-PERFORMANCE 6-CHANNEL AC’97 2.3 CODEC WITH UNIVERSAL JACKS

STAC9758/9759
HIGH-PERFORMANCE 6-CHANNEL AC’97 2.3 CODEC WITH UNIVERSAL JACKS™
PC AUDIO
2.2.4.
STAC9758/9759 Crystal Elimination Circuit and Clock Frequencies
The STAC9758/9759 supports several clock frequency inputs as described in the following table. In
general, when a 24.576MHz crystal is not used, the XTL_OUT pin should be tied to ground. This
short to ground configures the part into an alternate clock mode and enables an on board PLL.
CODEC Modes:
P = The STAC9758/9759 as a Primary CODEC
S = The STAC9758/9759 as a Secondary CODEC
Table 1. Clock Mode Configuration
XTL_OUT pin config
XTAL
short to ground
short to ground
XTAL or open
CID1 pin config
float
float
pulldown
pulldown
clock source input
24.576 MHz crystal
14.31818 MHz source
48 MHz source
12.288 MHz BIT_CLK
CODEC mode
P
P
P
S
CODEC ID
0
0
0
2
Whenever pin 3 is pulled down, the CODEC will be in primary mode with the CODEC ID 00 regard-
less of the state of CID1 pin. The only secondary mode operation available is with external device
sourcing BIT_CLK and CODEC ID = 2.
Table 2. Common Clocks and Sources
Clock Source
XTAL
BIT_CLK
VGA
USB
Clock Frequency
24.576 MHz
12.288 MHz
14.31818 MHz
48 MHz
Note: 1) Pin #2 (XTL_IN) may be left unconnected if CODEC is in secondary mode.
IDT™
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HIGH-PERFORMANCE 6-CHANNEL AC’97 2.3 CODEC WITH UNIVERSAL JACKS™
STAC9758/9759
V 1.2 1206