SAA7785 Datasheet, PDF (25/68 Pages) NXP Semiconductors – ThunderBird Avenger PCI Audio Accelerator

Philips Semiconductors
Preliminary Specification
ThunderBird Avenger^TM PCI Audio
Accelerator
SAA7785
PLL/DSPCLK SUBSYSTEM INTERFACE
CCLK
CODEC Clock Input
This pin is the raw 24.576MHz clock from the AC’97 crystal. The CCLK clock is used to provide
a fixed time base for many functions within the SAA7785 device.
DSPCLK
DSP Clock Input
This pin can be used as the clock input for the SAA7785 for the DSP subsystem in place of the
PLL driving the clock. DSPCLK is also used to drive the DSP subsystem for controllability dur-
ing testing.
PSUB
PLL Substrate
This pin supplies the bias for the guard ring on the PLL core. Connect this to a clean analog
supply ground.
PLLAPWR
PLL Analog Power
Analog power supply for the PLL. Be sure the analog supply is isolated from the 3 volt digital
supply.
PLLAGND
PLL Analog Ground
Analog ground for the PLL. This power supply is sensitive to noise and should be handled care-
fully.
POWER AND GROUND PINS
VDDIC
VSSIC
VSS
VDD
NWELL
Core Power
3 volt power supply for the core of the chip.
Core Ground
Ground reference for the core of the chip.
Ring Ground
Ground reference for the pad interfaces of the chip.
Ring Power
3 volt supply for the pad interfaces of the chip.
External N-Well Bias
Tie these pins to 5v for proper 5 volt tolerant operation. The 5v supply must be powered up
before the 3v supply. Likewise, the 3v supply must be powered down before the 5v supply.
PLEASE READ THE CAUTIONS IN Section 4.1, POWER SUPPLY OPERATING REQUIRE-
MENTS ***** MUST READ *****
1999 Nov 12
25