ICS9248-185 Datasheet, PDF (1/11 Pages) Integrated Circuit Systems – Frequency Generator & Integrated Buffers for PENTIUM/ProTM & K6

Integrated
Circuit
Systems, Inc.
ICS9248 - 185
Frequency Generator & Integrated Buffers for PENTIUM/Pro^TM & K6
Recommended Application:
VIA PM133 chipset
Output Features:
• 2 - CPUs @ 2.5V
• 5 - SDRAM @ 3.3V
• 3 - PCI @ 3.3V,
• 1 - 48MHz, @ 3.3V fixed.
• 2 - REF @ 3.3V, 14.318MHz.
Features:
• Up to 133MHz frequency support
• Support power management: PCI_STOP & CLK_STOP
• Spread spectrum for EMI control (-0.5% down spread).
• Uses external 14.318MHz crystal
• FS pins for frequency select
Key Specifications:
• CPU – PCI Skew: 1-4ns
• PCI – PCI Skew: ±500ps
• CPU – CPU Skew: ±175ps
• CPU Jitter: 250ps (cyc-cyc)
• PCI Jitter: 500ps (cyc-cyc)
Pin Configuration
VDD
1
REF0
2
GND
3
X1
4
X2
5
VDDPCI
6
1_{*PCICLK_F}
7
GND
8
1, 2_FS1/PCICLK0
9
BUFFER_IN 10
1_{PCICLK1 11}
PCI_STOP# 12
GND 13
*FS0/48MHz 14
28
REF1/FREE_SEL*¹
27 VDDL
26 CPUCLK0/_F
25 CPUCLK1
24 GND
23 CLK_STOP#
22 SDRAM0/_F
21 SDRAM1
20 SDRAM2
19 GND
18 VDDSDR
17 SDRAM3
16 SDRAM4
15 VDD48
28-Pin SSOP/TSSOP
* Internal Pull-up Resistor of 120K to VDD
1. These pin will have 2X drive strength
2. FS1 is a pull down
Block Diagram
PLL2
X1
X2
BUFFER_IN
PCI_STOP#
CLK_STOP#
FS (1:0)
XTAL
OSC
PLL1
Spread
Spectrum
Control
Logic
Config.
Reg.
CPU
DIVDER
Stop
Stop
PCI
DIVDER
Stop
48MHz
REF (1:0)
2
CPUCLK1
CPUCLK0/_F
4 ^{SDRAM (4:1)}
SDRAM0/_F
PCICLK (1:0)
2
PCICLK_F
Frequency Select
FS1 FS0 CPUCLK PCICLK
0
0
66.66
33.33
0
1
100.00
33.33
1
0
97.00
32.33
1
1
133.33
33.33
Down
Spread
-0.5%
-0.5%
-0.5%
-0.5%
9248-185 RevC - 10/25/01
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.