ICS9248-64 Datasheet, PDF (1/15 Pages) Integrated Circuit Systems – AMD-K7TM System Clock Chip

Integrated
Circuit
Systems, Inc.
ICS9248-64
AMD-K7^TM System Clock Chip
General Description
The ICS9248-64 is a main clock synthesizer chip for AMD-
K7 based systems. This provides all clocks required for such
a system when used with a Zero Delay Buffer Chip such as
the ICS9179-06.
Spread Spectrum may be enabled by driving the SPREAD#
pin active. Spread spectrum typically reduces system EMI by
8dB to 10dB. This simplifies EMI qualification without
resorting to board design iterations or costly shielding. The
ICS9248-64 employs a proprietary closed loop design, which
tightly controls the percentage of spreading over process and
temperature variations.
Features
• Generates the following system clocks:
- 3 differential pair open drain CPU clocks
(1.5V external
pull-up; up to 133MHz).
- 8 PCI including 1 free running (3.3V) @33.3MHz.
- 2 AGP(3.3V) up to 66.6MHz.
- 2 REF(3.3V)@14.318MHz
- 1 48MHz(3.3V)
- 24 / 48MHz(3.3V)
• Skew characteristics:
- CPU -CPU<250ps
- CPUt - CPUc <200ps (differential pair)
- PCI – PCI: <500ps
- CPU – SDRAM_OUT: < 250ps
- CPU – AGP <500ps
Block Diagram
• Efficient Power Management through PD#, PCI_STOP#
and CPU_STOP#.
• Spread Spectrum option for EMI reduction
(-1.0% down spread).
• Uses external 14.318 MHz crystal
Pin Configuration
*FS0/REF0
1
*FS1/REF1
2
GNDREF
3
X1
4
X2
5
GNDPCI
6
PCICLK_F
7
PCICLK0
8
VDDPCI
9
PCICLK1
10
PCICLK2
11
GNDPCI
12
PCICLK3
13
PCICLK4
14
VDDPCI
15
PCICLK5
16
PCICLK6
17
VDDAGP
18
AGP0
19
AGP1
20
GNDAGP
21
VDD48
22
48MHz
23
SEL24_48#/24-48MHz
24
48
VDDREF
47
GNDSD
46
SDRAM_OUT
45
VDDSD
44
RESERVED
43
CPUCLKC2
42
CPUCLKT2
41
GNDCPU
40
CUCLKC1
39
CPUCLKT1
38
GND
37
CPUCLKC0
36
CPUCLKT0
35
RESERVED
34
VDD
33
GND
32
PCI_STOP#
31
CPU_STOP#
30
PD#
29
SPREAD#
28
TEST#
27
26
SDATA
SCLK
I²C
25
GND48
48-Pin SSOP
* Internal 120K pullup resistor on indicated inputs
9248-64 Rev C 03/19/01
AMD-K is a trademark of Advanced Micro Devices.
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.