ICS9248-101 Datasheet, PDF (1/17 Pages) Integrated Circuit Systems – Frequency Generator & Integrated Buffers for PENTIUM/ProTM & K6

Integrated
Circuit
Systems, Inc.
ICS9248 - 101
Frequency Generator & Integrated Buffers for PENTIUM/Pro^TM & K6
General Description
The ICS9248-101 is the single chip clock solution for
Notebook designs using the 440BX or the VIAApollo Pro 133
style chipset. It provides all necessary clock signals for such a
system.
Spread spectrum may be enabled through I²C programming.
Spread spectrum typically reduces system EMI by 8dB to
10dB. This simplifies EMI qualification without resorting to
board design iterations or costly shielding. The ICS9248-101
employs a proprietary closed loop design, which tightly
controls the percentage of spreading over process and
temperature variations.
Block Diagram
Features
• Up to 137MHz frequency support
• Spread Spectrum for EMI control
• Serial I²C interface for Power Management,
Frequency Select, Spread Spectrum.
• Provides the following system clocks
- 4-CPUs @ 2.5/3.3V, up to 137MHz.
(including CPUCLK_F)
- 9-SDRAMs @3.3V, up to 137MHz
(including SDRAM_F)
- 8-PCI @3.3V, CPU/2 or CPU/3
(including 1 free running PCICLK_F)
- 1-24/48MHz @3.3V
- 1-48MHz @3.3V fixed
- 2-REF @3.3V, 14.318MHz.
• Efficient Power management scheme through PCI
and STOP CLOCKS
• Spread Spectrum ± .25%, & 0 to -0.5% down spread
Power Groups
VDDLCPU, GNDLCPU = CPUCLK [2:0], CPUCLK_F
VDDSDR, GNDSDR = SDRAMCLKS [7:0], SDRAM_F
VDDPCI, GNDPCI = PCICLKS [6:0], PCICLK_F
VDD48, GND48 = 48MHz, 24MHz
VDDREF, GNDREF = REF, X1, X2
VDDCOR = PLL CORE
9248-101 Rev C 2/29/00
Pin Configuration
VDDREF
1
REF0
2
GNDREF
3
X1
4
X2
5
VDDPCI
6
*CPU2.5_3.3#/PCICLK_F
7
*FS3/PCICLK0
8
GNDPCI
9
*SEL24_48#/PCICLK1
10
PCICLK2
11
PCICLK3
12
PCICLK4
13
VDDPCI
14
BUFFER IN
15
GNDPCI
16
PCICLK5
17
PCICLK6
18
VDDCOR
19
PCI_STOP#
20
*PD#
21
GND48
22
{ I ² C
SDATA
SCLK
23
24
48
REF1/FS2*
47
VDDLCPU
46
CPUCLK_F
45
CPUCLK0
44
GNDLCPU
43
CPUCLK1
42
CPUCLK2
41
CLK_STOP#
40
GNDSDR
39
SDRAM_F
38
SDRAM0
37
SDRAM1
36
VDDSDR
35
SDRAM2
34
SDRAM3
33
GNDSDR
32
SDRAM4
31
SDRAM5
30
VDDSDR
29
SDRAM6
28
SDRAM7
27
VDD48
26
48MHz/FS0*
25
24_48MHz/FS1*
48-Pin SSOP and TSSOP
* Internal Pull-up Resistor of 120K to VDD
Pentium is a trademark of Intel Corporation
I²C is a trademark of Philips Corporation
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.