ICS9248-126 Datasheet, PDF (1/12 Pages) Integrated Circuit Systems – Frequency Generator & Integrated Buffers for Celeron & PII/III™ & K6

Integrated
Circuit
Systems, Inc.
ICS9248-126
Frequency Generator & Integrated Buffers for Celeron & PII/III™ & K6
Recommended Application:
Motherboard Single chip clock solution for Pentium II/III and
K6 processors, using SIS540/SIS630 style chipset.
Output Features:
• 3- CPUs @ 2.5/3.3V, up to 166MHz.
• 14 - SDRAM @ 3.3V
• 7- PCI @3.3V,
• 1- 48MHz, @3.3V fixed.
• 1- 24/48MHz, @3.3V selectable by I²C
(Default is 24MHz).
• 2- REF @3.3V, 14.318MHz.
Features:
• Up to 166MHz frequency support
• Support FS0-FS3 trapping status bit for I²C read back.
• Support power management: CPU, PCI, SDRAM stop
and Power down Mode form I²C programming.
• Spread spectrum for EMI control (0 to -0.5%, ± 0.25%).
• FS0, FS1, FS3 must have a internal 120K pull-Down
to GND.
• Uses external 14.318MHz crystal
Skew Specifications:
• CPU - CPU: < 175ps
• SDRAM - SDRAM < 500ps
• PCI - PCI: < 500ps
• CPU - SDRAM: < 500ps
• CPU - PCI: 1 - 4ns
Pin Configuration
VDDREF
1
*¹REF0/FS3
2
GND
3
X1
4
X2
5
VDDPCI
6
*PCICLK0/FS1
7
*PCICLK1/FS2
8
PCICLK2
9
GND
10
PCICLK3
11
PCICLK4
12
PCICLK5
13
PCICLK6
14
VDDSDR
15
GND
16
SDRAM0
17
SDRAM1
18
VDDSDR
19
SDRAM2
20
SDRAM3
21
GND
22
SDATA
23
SCLK
24
48
REF1
47
VDDLCPU
46
CPUCLK0
45
CPUCLK1
44
GND
43
CPUCLK2
42
VDDSDR
41
SDRAM13
40
SDRAM12
39
GND
38
SDRAM11
37
SDRAM10
36
VDDSDR
35
SDRAM9
34
SDRAM8
33
GNDSDR
32
SDRAM7
31
SDRAM6
30
VDDSDR
29
SDRAM5
28
SDRAM4
27
VDDSDR
26
48MHz/FS0*¹
25
24_48MHz/CPU2.5_3.3#*
48-Pin 300mil SSOP
* These inputs have a 120K pull down to GND.
1 These are double strength.
Block Diagram
PLL2
X1
XTAL
X2
OSC
48MHz
/2
24_48MHz
2 ^{REF (1:0)}
FS(3:0) ⁴
CPU2.5_3.3#
SDATA
SCLK
PLL1
Spread
Spectrum
LATCH
CPU
CLOCK
DIVDER
SDRAM
CLOCK
DIVDER
Control
Logic
Config.
Reg.
PCI
CLOCK
DIVDER
3 ^{CPUCLK (2:0)}
14 ^{SDRAM (13:0)}
PCICLK (6:0)
7
Functionality
FS3 FS2
FS1
FS0
CPU
(MHz)
SDRAM
(MHz)
PCICLK
(MHz)
0 0 0 0 66.6
100.0
33.3
0 0 0 1 100.0 100.0
33.3
0 0 1 0 150.0 100.0
37.5
0 0 1 1 133.3 100.0
33.3
010 0
66.8
133.6
33.4
0 1 0 1 100.0 133.3
33.3
0 1 1 0 100.0 150.0
37.5
0 1 1 1 133.3 133.3
33.3
1 0 0 0 66.8
66.8
33.4
1 0 0 1 97.0
97.0
32.3
1 0 1 0 70.0
105.0
35.0
1 0 1 1 95.0
95.0
31.7
1 1 0 0 95.0
126.7
31.7
1 1 0 1 112.0 112.0
37.3
1 1 1 0 97.0
129.3
32.2
1 1 1 1 96.2
96.2
32.1
9248-126 Rev C 9/6/00
Third party brands and names are the property of their respective owners.
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.