ICS9FG107 Datasheet, PDF (4/18 Pages) Integrated Circuit Systems – Programmable FTG for Differential CPU, PCI Express & SATA Clocks

ICS9FG107
Programmable FTG for Differential P4^TM CPU, PCI-Express & SATA Clocks
Pin Description (Continued)
PIN #
PIN NAME
PIN TYPE
DESCRIPTION
25
DIF_STOP#
IN
Active low input to stop differential output clocks.
26
SPREAD*
IN
Asynchronous, active high input, with internal 120Kohm pull-up
resistor, to enable spread spectrum functionality.
27
SEL14M_25M#**
Select 14.31818 MHz or 25 Mhz input frequency. 1 = 14.31818 MHz,
IN
0 = 25 MHz
28
OE_3*
IN
Active high input for enabling output 3.
0 = tri-state outputs, 1= enable outputs
29
DIF_3#
OUT
0.7V differential complement clock output
30
DIF_3
OUT
0.7V differential true clock output
31
VDD
PWR
Power supply, nominal 3.3V
32
DIF_2#
OUT
0.7V differential complement clock output
33
DIF_2
OUT
0.7V differential true clock output
34
OE_2**
Active high input for enabling output 2.
IN
0 = tri-state outputs, 1= enable outputs
35
GND
PWR
Ground pin.
36
VDD
PWR
Power supply, nominal 3.3V
37
OE_1**
IN
Active high input for enabling output 1.
0 = tri-state outputs, 1= enable outputs
38
DIF_1#
OUT
0.7V differential complement clock output
39
DIF_1
OUT
0.7V differential true clock output
40
VDD
PWR
Power supply, nominal 3.3V
41
DIF_0#
OUT
0.7V differential complement clock output
42
DIF_0
OUT
0.7V differential true clock output
43
OE_0*
IN
Active high input for enabling output 0.
0 = tri-state outputs, 1= enable outputs
44
FS1**
IN
3.3V Frequency select latched input pin.
3.3V input that selects spread mode. This input is not latched at
45
DWNSPRD#*
IN
power up.
0 = Down Spread, 1 = Center Spread
This pin establishes the reference current for the differential current-
46
IREF
OUT
mode output pairs. This pin requires a fixed precision resistor tied to
ground in order to establish the appropriate current. 475 ohms is the
standard value.
47
GNDA
PWR
Ground pin for the PLL core.
48
VDDA
PWR
3.3V power for the PLL core.
Pins preceeded by * have 120 Kohm pull UP resistors
Pins preceeded by ** have 120 Kohm pull DOWN resistors
IDT^TM/ICS^TM Programmable FTG for Differential P4^TM CPU, PCI-Express & SATA Clocks
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ICS9FG107 REV F 08/21/07