ICS9169C-272 Datasheet, PDF (1/8 Pages) Integrated Circuit Systems – Frequency Generator for Pentium™ Based Systems

Integrated
Circuit
Systems, Inc.
ICS9169C-272
Frequency Generator for Pentium™ Based Systems
General Description
Features
The ICS9169C-272 is a low-cost frequency generator •
designed specifically for Pentium based chip set systems. •
The integrated buffer minimizes skew and provides all the _•
clocks required. A 14.318 MHz XTAL oscillator provides
the reference clock to generate standard Pentium frequencies.
•
The CPU clock makes gradual frequency transitions without
violating the PLL timing of internal microprocessor clock
multipliers.A raised frequency setting of 68.5MHz is available
•
•
in the Turbo-mode of the 66.8MHz CPU. The ICS9169C-272 ^•
contains 12 CPU clocks, 4 PCI clocks, 1 REF at 48MHz and 1 at
24MHz.
•
•
The twelve CPU clock outputs provide sufficient clocks for
the CPU, chip set, memory and up to two DIMM connectors _•
(with four clocks to each DIMM). Either synchronous(CPU/
2) or asynchronous (32 MHz) PCI busoperation can be selected
by latching data on the BSEL input
Block Diagram
Twelve selectable CPU clocks operate up to 83.3MHz
Maximum CPU jitter of ± 200ps
Six BUS clocks support sync or async bus operation
250ps skew window for CPU outputs, 500ps skew
window for BUS outputs
CPU clocks BUS clocks skew 1-4ns (CPU early)
Integrated buffer outputs drive up to 30pF loads
3.0V - 3.7V supply range, CPU(1:6) outputs 2.5V(2.375-
2.62V) VDD option
32-pin SOIC/SOJ package
Logic inputs latched at Power-On for frequency selection
saving pins as Input/Output
48 MHz clock for USB support and 24 MHz clock
for FD.
Pin Configuration
VDD Groups:
VDD1 = X1, X2, REF/BSEL
VDDC1 = CPU1-6
VDDC2 = CPU7-12 & PLL Core
VDDB = BUS1-6
VDDF = 48/24 MHz
Latched Inputs:
L1 = BSEL
L2 = FS0
L3 = FS1
L4 = FS2
9169C-272RevC060297P
32-Pin SOIC/SOJ
Functionality
3.3V±10%, 0-70^°C
Crystal (X1, X2) = 14.31818 MHz
ADDRESS
SELECT
FS2 FS1 FS0
00 0
00 1
01 0
01 1
10 0
10 1
11 0
11 1
CPU(1:12)
(MHz)
50
60
66.8
75.9
55
75.9
83.3
68.5
BUS (1:6)MHz
BSEL=1
25
30
33.4
32
27.5
37.5
41.7
34.25
BSEL=0
32
32
32
32
32
32
32
32
48MHz
48
48
48
48
48
48
48
48
24MHz
24
24
24
24
24
24
24
24
REF
REF
REF
REF
REF
REF
REF
REF
REF
Pentium is a trademark of Intel 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.