ICS9169C-41 Datasheet, PDF (6/7 Pages) Integrated Circuit Systems – Frequency Generator for PentiumPro™ Based Systems

ICS9169C-41
Technical Pin Function Descriptions
VDD
This is the power supply to the internal logic of the device as
well as the following clock output buffers:
This pin may be operated at any voltage between 3.0 and 3.7
volts. Clocks from the listed buffers that it supplies will
have a voltage swing from ground to this level. For the
actual guaranteed high and low voltage levels of these clocks,
please consult the AC parameter table in this data sheet.
GND
This is the power supply ground return pin.
X1
This pin serves one of two functions. When the device is
used with a crystal, X1 acts as the input pin for the reference
signal that comes from the discrete crystal. When the device
is driven by an external clock signal, X1 is the device input
pin for that reference clock. This pin also implements an
internal crystal loading capacitor that is connected to ground.
See the data tables for the value of the capacitor.
X2
This pin is used only when the device uses a Crystal as the
reference frequency source. In this mode of operation, X2 is
an output signal that drives (or excites) the discrete crystal.
This pin also implements an internal crystal loading capacitor
that is connected to ground. See the data tables for the value
of the capacitor.
CPU (1:12)
These pins are the clock output that drive the processor and
other CPU related circuitry that require clocks which are in
tight skew tolerance with the CPU clock. See the
Functionality table at the beginning of this data sheet for a
list of the specific frequencies that these clocks operate at
and the selection codes that are necessary to produce these
frequencies. Some of these pin serve dual functions.
PCICLK
Clock output driver for the PCI Bus.
FS0, FS1, FS2
These pins control the frequency of the clocks at the CPU,
BUS and SDRAM pins. See the Funtionality table at the
beginning of this data sheet for a list of the specific
frequencies that these clock operate at and the selection
codes that are necessary to produce these frequencies. The
device reads these pins at power-up and stores the
programmed selection code in an internal data latch. If a "1"
value is desired for a specific frequency selection bit,a 10K
ohm resistor must be connected from the appropriate FS pin
to the VDD supply. If a "O" value is desired, then the 10K
resistor must be connected to ground. After the internal
power On reset latches the input data, these pins become
output clocks and no further frequency selection is possible.
48MHz
This is a fixed frequency clock that is typically used to drive
USB peripheral device needs.
24MHz
This is a fixed frequency clock that is typically used to drive
super I/O peripheral device needs.
REF (0:1)
This is a fixed frequency clock that runs at the same frequency
as the input freerence clock (typically 14.31818 MHz) is
and typically used to drive Video and ISA BUS requirements.
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