ICS9248-157 Datasheet, PDF (1/11 Pages) Integrated Circuit Systems – Frequency Timing Generator for Pentium II Systems

Integrated
Circuit
Systems, Inc.
ICS9248-157
Frequency Timing Generator for Pentium II Systems
Recommended Application:
ALI1621/1632M style chipsets
Output Features:
• 2 - CPUs @2.5V, up to 140MHz.
• 7 - PCI @3.3V, (including one free running)
• 1 - 48MHz, @3.3V fixed.
• 2 - REF @3.3V, 14.318MHz.
Features:
• Up to 140 MHz frequency support
• Support power management: CPU, PCI stop and
Power down.
• Spread spectrum for EMI control (0.5% down spread).
• Uses external 14.318MHz crystal
• FS pins for frequency select
Key Specifications:
• CPU – CPU: <175ps
• PCI – PCI: <250ps
• CPU(early)-PCI: 1.5ns - 4ns
• PCI_E (early) - PCI: 2.1ns
Pin Configuration
*FS1/REF0
1
X1
2
X2
3
**FS2/PCICLK_F
4
*SEL_CPUF#/PCICLK0
5
PCICLK1
6
GND
7
VDDPCI
8
PCICLK2
9
PCICLK3 ¹⁰
PCICLK4 ¹¹
PCICLK_E ¹²
VDD48 13
*FS3/48MHz 14
28 _VDDR
27 REF1/FS0*
26 SPREAD#
25 VDDL
24 CPUCLK1
23 CPUCLK0/F
22 GNDL
21 GND
20 PCI_STOP#
19 VDDA
18 CPU_STOP#
17 PD#
16 DIV/4#
15 GND
28 Pin 209mil SSOP
*These inputs have a 120K pull up to VDD
**These inputs have a 120K pull down to GND
Block Diagram
X1
X2
CPU_STOP#
FS (3:0)
PD#
Div4#
SPREAD#
SEL_CPUF#
PCI_STOP#
OSC
PLL
Spread
Spectrum ^{/ 4}
Glitch
Free
Control
Logic
/2
/3
PLL2
CPU
STOP
CPU
STOP
BUS
STOP
2 ^{REF (1:0)}
2 ^{CPUCLK 1}
CPUCLK0/F
PCICLK (4:0),
5 _{PCICLK_E}
PCICLK_F
48MHz
Functionality
FS3 FS2 FS1 FS0
0
0
0
0
0
0
0
1
0
0
1
0
0
0
1
1
0
1
0
0
0
1
0
1
0
1
1
0
0
1
1
1
1
0
0
0
10
0
1
10
1
0
10
1
1
1
1
0
0
1
1
0
1
1
1
1
0
1
1
1
1
CPU
33.33
63.33
69.99
66.66
97.00
96.22
91.50
83.33
50.00
95.25
105.00
100.00
66.66
126.35
139.65
133.33
PCI
16.66
31.66
35.00
33.33
32.33
32.07
30.50
27.77
16.66
31.75
35.00
33.33
16.66
31.66
35.00
33.33
9248-157 Rev A - 1/16/01
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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