Integrated
Circuit
Systems, Inc.
ICS9248-107
Frequency Timing Generator for PENTIUM II Systems
RecommendedApplication:
Pin Configuration
RCC chipset
GNDREF
REF0
*SEL24_48#/REF1
VDDREF
X1
1
2
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
VDDLAPIC
IOAPIC0
IOAPIC1
GNDLAPIC
IOAPIC2
VDDLCPU
CPUCLK0
GNDLCPU
CPUCLK1
VDDLCPU
CPUCLK2
CPUCLK3
GNDLCPU
VDD66
OutputFeatures:
3
4
5
6
7
8
9
•
•
•
•
•
•
4 - CPUs @ 2.5V, up to 180MHz.
X2
GNDPCI
3-IOAPIC@2.5V
3-3V66MHz@3.3V.
11-PCIs@3.3V
*FS0/PCICLK_F
*FS1/PCICLK1
VDDPCI
*FS2/PCICLK2
*FS3/PCICLK3
GNDPCI
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
1-48MHz,@3.3Vfixed
1-24/48MHz,@3.3V
PCICLK4
PCICLK5
VDDPCI
PCICLK6
PCICLK7
GNDPCI
PCICLK8
PCICLK9
PCICLK10
VDDPCI
3V66_0
3V66_1
3V66_2
GND66
SDATA
SCLK
VDD48
48MHz/FS4*
24_48MHz
GND48
Features:
•
•
Up to 180MHz frequency support
I2
C
{
Use a zero delay buffer such as the ICS9179-06 to
generate SDRAM clocks.
PD#
•
•
Support power management: Power down Mode
fromI2Cprogramming.
48-pin SSOP
*120K ohm pull-up to VDD on indicated inputs.
Spread spectrum for EMI control
± 0.25% center spread).
•
•
Usesexternal14.318MHzcrystal
5 - FS pins for frequency select
KeySpecifications:
•
•
•
•
•
•
•
•
•
•
•
CPU Output Jitter: <250ps
IOAPIC Output Jitter: <500ps
Block Diagram
48MHz, 3V66, PCIOutputJitter:<500ps
Ref Output Jitter. <1000ps
PLL2
48MHz
CPUOutputSkew:<175ps
24_48MHz
/ 2
IOAPIC Output Skew <250ps
X1
X2
XTAL
OSC
REF(1:0)
PCIOutputSkew:<580ps
3V66OutputSkew<250ps
PLL1
Spread
CPU
DIVDER
CPUCLK (3:0)
IOAPIC (2:0)
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)
Spectrum
IOAPIC
DIVDER
SEL24_48#
SDATA
PCI
DIVDER
Control
Logic
PCICLK (10:0)
PCICLK_F
I2C
{
SCLK
FS(4:0)
Config.
Reg.
3V66
DIVDER
3V66 (2:0)
PD#
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
9248-107RevA -5/21/01
information being relied upon by the customer is current and accurate.