ICS9250-12 Datasheet, PDF (3/12 Pages) Integrated Circuit Systems – Frequency Timing Generator for PENTIUM II/III Systems

ICS9250-12
Frequency Select:
SEL
133/100- SEL1 SEL0
#
CPU
MHz
0
0
0 Hi-Z
0
0
1 N/A
CPU/2
MHz
Hi-Z
N/A
3V66
MHz
Hi-Z
N/A
PCI
MHz
Hi-Z
N/A
48
MHz
Hi-Z
N/A
REF
MHz
Hi-Z
N/A
IOAPIC
MHz
Hi-Z
N/A
0
1 0 100
50
66
33 Hi-Z 14.318 16.67
0
1
1 100
50
66
33
48 14.318 16.67
1
0
0
TCLK/2 TCLK/4
TCLK/4
TCLK/8
TCLK/-
2
TCLK
TCLK/16
1
0
1 N/A N/A N/A N/A N/A N/A N/A
1
1 0 133
66
66
33 Hi-Z 14.318 16.67
1
1
1 133
66
66
33
48 14.318 16.67
Note:
1. TCLK is a test clock driven on the x1 input during test mode.
Comments
Tri-state
Reserved
48MHz PLL
disabled
Test mode (1)
Reserved
ICS9250-12 Power Management Features:
CPU_STOP#
X
PD# PCI_STOP# CPUCLK CPU/2 IOAPIC 3V66
0
X
LOW LOW LOW LOW
PCI
PCI_F
REF.
48MHz
Osc
LOW LOW LOW OFF
VCOs
OFF
0
1
0
LOW ON
ON LOW LOW ON
ON ON
ON
0
1
1
LOW ON
ON LOW ON
ON
ON ON
ON
1
1
0
ON
ON
ON
ON LOW ON
ON ON
ON
1
1
1
ON
ON
ON
ON ON
ON
ON ON
ON
Note:
1. LOW means outputs held static LOW as per latency requirement next page.
2. On means active.
3. PD# pulled Low, impacts all outputs including REF and 48 MHz outputs.
4. All 3V66 as well as all CPLU clocks should stop cleanly when CPU_STOP# is pulled LOW.
5. CPU/2, IOAPIC, REF, 48 MHz signals are not controlled by the CPU_STOP# functionality and are enabled all in all conditions
except PD# = LOW
Power Groups:
VDDREF, GNDREF = REF, X1, X2
GNDPCI, VDDPCI = PCICLK
VDD66, GND66 = 3V66
VDD48, GND48 = 48MHz
VDDCOR, GNDCOR = PLL Core
VDDLCPU/2 , GNDLCPU/2 = CPU/2
VDDLIOAPIC, GNDIOAPIC = IOAPIC
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