ICS9248-135 Datasheet, PDF (1/15 Pages) Integrated Circuit Systems – Frequency Generator & Integrated Buffers for Celeron & PII/III™& K6

Integrated
Circuit
Systems, Inc.
ICS9248-135
Frequency Generator & Integrated Buffers for Celeron & PII/III™& K6
Recommended Application:
Motherboard Single chip clock solution for SIS540,
SIS630 Pentium II/III and K6 chipsets.
Output Features:
• 3- CPUs @ 2.5/3.3V, up to 166MHz.
• 10 - SDRAM @ 3.3V, up to 166MHz
including 2 SDRAM_F's
• 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 < 250ps
• PCI - PCI: < 500ps
• CPU - SDRAM: < 500ps
• CPU (early) - PCI: 1-4ns (typ. 2ns)
Pin Configuration
VDDREF
1
*¹REF0/FS3
2
GNDREF
3
X1
4
X2
5
VDDPCI
6
*PCICLK_F/FS1
7
*PCICLK1/FS2
8
PCICLK2
9
GNDPCI
10
PCICLK3
11
PCICLK4
12
PCICLK5
13
PCICLK6
14
VDD
15
GND
16
SDRAM_STOP#
17
**PD#
18
VDD
19
CPU_STOP#
20
PCI_STOP#
21
GND
22
SDATA
23
SCLK
24
48 REF1
47 VDDLCPU
46 CPUCLK_F
45 CPUCLK1
44 GNDL
43 CPUCLK2
42 VDD
41 SDRAM_F1
40 SDRAM_F0
39 GND
38 SDRAM7
37 SDRAM6
36 VDD
35 SDRAM5
34 SDRAM4
33 GND
32 SDRAM3
31 SDRAM2
30 VDD
29 SDRAM1
28 SDRAM0
27 VDD
26
48MHz/FS0*¹
25 24_48MHz/CPU2.5_3.3#*
48-Pin 300mil SSOP
* These inputs have a 120K pull down to GND.
** These inputs have a 120K pullup to VDD.
1 These are double strength.
Block Diagram
PLL2
X1
XTAL
X2
OSC
PLL1
Spread
Spectrum
CPU2.5_3.3#
SDATA
SCLK
FS[3:0]
PD#
PCI_STOP#
CPU_STOP#
SDRAM_STOP#
Control
Logic
Config.
Reg.
/2
CPU
DIVDER
Stop
SDRAM
DIVDER
Stop
PCI
DIVDER
Stop
48MHz
24_48MHz
2 ^REF[1:0]
2 ^{CPUCLK [2:1]}
CPUCLK_F
8 ^{SDRAM [7:0]}
SDRAM_F [1:0]
2
PCICLK [6:1]
6
PCICLK_F
Functionality
FS3 FS2
FS1
FS0
CPU
(MHz)
SDRAM
(MHz)
PCICLK
(MHz)
000 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
9248-135 Rev A 1/16/01
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.