Integrated
Circuit
Systems, Inc.
General Description
Features
ICS9148-82
Block Diagram
Pentium is a trademark of Intel Corporation
I
2C is a trademark of Philips Corporation
Frequency Generator & Integrated Buffers for PENTIUM/ProTM
9148-82 Rev A 3/25/99
Pin Configuration
48-Pin SSOP
Power Groups
VDD1=REF(0:1),X1,X2
VDD2=PCICLK_F,PCICLK(0:5)
VDD3 = SDRAM (0:12), supply for PLL core
VDD4=AGP(1:2)
VDD5=FixedPLL,48MHz,AGP0
VDDL= CPUCLK(0:2)
* Internal Pull-up Resistor of
240K to 3.3V on indicated inputs
The ICS9148-82 generates all clocks required for high speed
RISC or CISC microprocessor systems such as Intel PentiumPro
or Cyrix. Eight different reference frequency multiplying factors
are externally selectable with smooth frequency transitions.
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 ICS9148-82
employs a proprietary closed loop design, which tightly
controls the percentage of spreading over process and
temperature variations.
Serial programming I2C interface allows changing functions,
stop clock programming and frequency selection. The
SDRAM12 output may be used as a feed back into an off chip
PLL.
Generates the following system clocks:
-3CPU(2.5V/3.3V)upto100MHz.
-6PCI(3.3V)@ 33.3MHz
-3AGP(3.3V)@2x PCI
- 13 SDRAMs(3.3V) up to 100MHz
-1REF(3.3V)@14.318MHz
Skew characteristics:
- CPU CPU<250ps
- CPU(early) PCI : 1-4ns, Center 2.6ns
-AGP- PCI: 500ps
Supports Spread Spectrum modulation & I2C
programming for Power Management, Frequency Select
Efficient Power management scheme through PCI and
CPUSTOPCLOCKS.
Uses external 14.318MHz crystal
48pin300milSSOP.
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.