ICS9248-107 Datasheet, PDF (1/14 Pages) Integrated Circuit Systems – Frequency Timing Generator for PENTIUM II Systems

Integrated
Circuit
Systems, Inc.
ICS9248-107
Frequency Timing Generator for PENTIUM II Systems
Recommended Application:
RCC chipset
Output Features:
• 4 - CPUs @ 2.5V, up to 180MHz.
• 3 - IOAPIC @ 2.5V
• 3 - 3V66MHz @ 3.3V.
• 11 - PCIs @ 3.3V
• 1 - 48MHz, @ 3.3V fixed
• 1 - 24/48MHz, @ 3.3V
Features:
• Up to 180MHz frequency support
• Use a zero delay buffer such as the ICS9179-06 to
generate SDRAM clocks.
• Support power management: Power down Mode
from I²C programming.
• Spread spectrum for EMI control
± 0.25% center spread).
• Uses external 14.318MHz crystal
• 5 - FS pins for frequency select
Key Specifications:
• CPU Output Jitter: <250ps
• IOAPIC Output Jitter: <500ps
• 48MHz, 3V66, PCI Output Jitter: <500ps
• Ref Output Jitter. <1000ps
• CPU Output Skew: <175ps
• IOAPIC Output Skew <250ps
• PCI Output Skew: <580ps
• 3V66 Output Skew <250ps
• CPU to 3V66 Output Offset: 0.8 - 1.8ns (typ = 1.3ns)
• CPU to PCI Output Offset: 0.0 - 1.5ns (typ = 1.0ns)
• CPU to IOAPIC Output Offset: 1.5 - 4.0ns (typ = 2.0ns)
Pin Configuration
GNDREF
1
REF0
2
*SEL24_48#/REF1
3
VDDREF
4
X1
5
X2
6
GNDPCI
7
*FS0/PCICLK_F
8
*FS1/PCICLK1
9
VDDPCI
10
*FS2/PCICLK2
11
*FS3/PCICLK3
12
GNDPCI
13
PCICLK4
14
PCICLK5
15
VDDPCI
16
PCICLK6
17
PCICLK7
18
GNDPCI
19
PCICLK8
20
PCICLK9
21
PCICLK10
22
VDDPCI
23
PD#
24
48
VDDLAPIC
47
IOAPIC0
46
IOAPIC1
45
GNDLAPIC
44
IOAPIC2
43
VDDLCPU
42
CPUCLK0
41
GNDLCPU
40
CPUCLK1
39
VDDLCPU
38
CPUCLK2
37
CPUCLK3
36
GNDLCPU
35
VDD66
34
3V66_0
33
3V66_1
32
3V66_2
31
GND66
30
29
SDATA
SCLK
I²C
28
VDD48
27
48MHz/FS4*
26
24_48MHz
25
GND48
48-pin SSOP
*120K ohm pull-up to VDD on indicated inputs.
Block Diagram
PLL2
X1
XTAL
X2
OSC
PLL1
Spread
Spectrum
SEL24_48#
{ ^I2C
SDATA
SCLK
FS(4:0)
PD#
Control
Logic
Config.
Reg.
/2
CPU
DIVDER
IOAPIC
DIVDER
PCI
DIVDER
3V66
DIVDER
48MHz
24_48MHz
REF(1:0)
CPUCLK (3:0)
IOAPIC (2:0)
PCICLK (10:0)
PCICLK_F
3V66 (2:0)
9248-107 RevA - 5/21/01
ICS reserves the right to make changes in the device data identified in
this publication without further notice. ICS advises its customers to
obtain the latest version of all device data to verify that any
information being relied upon by the customer is current and accurate.