ICS9248-87 Datasheet, PDF (1/13 Pages) Integrated Circuit Systems – Frequency Generator & Integrated Buffers for Celeron & PII/III™

Integrated
Circuit
Systems, Inc.
ICS9248-87
Preliminary Product Preview
Frequency Generator & Integrated Buffers for Celeron & PII/III™
Recommended Application:
810/810E type chipset.
Output Features:
• 2- CPUs @2.5V, up to 155MHz.
• 9 - SDRAM @ 3.3V, up to 155MHz.
• 8 - PCICLK @ 3.3V
• 1 - IOAPIC @ 2.5V,
• 2 - 3V66MHz @ 3.3V
• 2- 48MHz, @3.3V fixed.
• 1- 24/48MHz, @3.3V
• 1- REF @3.3V, 14.318MHz.
Features:
• Up to 155MHz frequency support
• Support FS0-FS3 strapping status bit for I²C read back.
• Support power management: Power down Mode from I²C
programming.
• Spread spectrum for EMI control ( ± 0.25% center).
• Uses external 14.318MHz crystal
Skew Specifications:
• CPU – CPU: <175ps
• SDRAM - SDRAM: < 250ps
• 3V66 – 3V66: <175ps
• PCI – PCI: <500ps
• For group skew specification, please refer to group
timing relationships table.
Pin Configuration
48-Pin 300mil SSOP
*: These inputs have a 120K pull up to VDD.
1: These are double strength.
Block Diagram
Functionality
PLL2
X1
XTAL
X2
OSC
PLL1
Spread
Spectrum
SEL24_48#
{ ^I2C
SDATA
SCLK
FS[3:0]
PD#
Control
Logic
Config.
Reg.
/2
CPU
DIVDER
SDRAM
DIVDER
IOAPIC
DIVDER
PCI
DIVDER
3V66
DIVDER
48MHz
2
24_48MHz
REF1
CPUCLK [1:0]
2
SDRAM [7:0]
8
SDRAM_F
IOAPIC
PCICLK [7:0]
8
3V66 [1:0]
2
FS3 FS2 FS1 FS0
0000
0001
00 10
00 11
0 100
0 10 1
0 110
0111
10 0 0
100 1
10 10
10 11
1100
110 1
1 1 10
1111
CPU CPU/ SDRAM
(MHz) SDRAM (MHz)
83.3
124.00
155.00
143.96
70.00
112.00
150.00
140.00
68.33
107.00
138.00
137.33
66.80
100.30
133.60
133.60
1.00 83.3
1.00 124.00
1.00 155.00
1.33 108.00
0.67 105.00
1.00 112.00
1.00 150.00
1.33 105.00
0.67 102.50
1.00 107.00
1.00 138.00
1.33 103.00
0.67 100.20
1.00 100.30
1.00 133.60
1.33 100.20
3V66
(MHz)
PCICLK
(3V66*
1/2)
(MHz)
IOAPIC
(PCI*
1/2)
(MHz)
IOAPIC
(PCI)
(MHz)
55.48 27.74 13.87 27.74
82.67 41.33 20.67 41.33
103.33 51.67 25.83 51.67
72.00 36.00 18.00 36.00
70.00 35.00 17.50 35.00
74.67 37.33 18.67 37.33
100.00 50.00 25.00 50.00
70.00 35.00 17.50 35.00
68.33 34.17 17.08 34.17
71.33 35.67 17.83 35.67
92.00 46.00 23.00 46.00
68.67 34.34 17.17 34.34
66.80 33.40 16.70 33.40
66.80 33.40 16.70 33.40
89.07 44.53 22.27 44.53
66.80 33.40 16.70 33.40
9248-87 Rev D 10/27/00
Third party brands and names are the property of their respective owners.
PRODUCT PREVIEW documents contain information on new
products in the sampling or preproduction phase of development.
Characteristic data and other specifications are subject to change
without notice.