ICS9169C-231 Datasheet, PDF (1/8 Pages) Integrated Circuit Systems – Frequency Generator for Pentium Based Systems

Integrated
Circuit
Systems, Inc.
ICS9169C-231
Frequency Generator for Pentium™ Based Systems
General Description
The ICS9169C-231 is a low-cost frequency generator
designed specifically for Pentium and Pentium-Pro 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 68.5 MHz is available for Turbo-mode
of the 66.8 MHz CPU. The ICS9169C-231 contains 8 CPU
clocks, 6 PCI clocks, 1 REF at 48MHz and 1 at 24MHz.
Either synchronous (CPU/2) or asynchronous (32 MHz)
PCI bus operation can be selected by latching data on
BSEL input.
Block Diagram
Features
• Eight selectable CPU clocks operate up to 83.3 MHz
• Frequency selections include Turbo-mode speed of
68.5 MHz
• 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 to BUS clocks skew 1-4 ns (CPU early)
• 48 MHz clock for USB support & 24 MHz clock for FD.
• Logic inputs latched at Power-On for frequency
selection saving pins as Input/Output
• Integrated buffer outputs drive up to 30pF loads
• 3.0V - 3.7V supply range, CPU (1:8) outputs 2.5V
(2.375 - 2.6V) VDD option
• 28-pin SOIC or SSOP package
Pin Configuration
VDD Groups:
VDD1 = X1, X2, REF/BSEL
VDD2 = CPU1-6
VDD3 = CPU7-8 & PLL Core
VDD4 = BUS1-6
VDD5 = 48/24 MHz
Latched Inputs:
L1 = BSEL
L2 = FS0
L3 = FS1
L4 = FS2
9169C-231RevB040697P
28-Pin SOIC or SSOP
Functionality
3.3V±10%, 0-70^°C
Crystal (X1, X2) = 14.31818 MHz
ADD RESS
S EL ECT
FS2 FS1 FS0
00
0
00
1
01
0
01
1
10
0
10
1
11
0
11
1
CPU(1:8) BU S (1:6)MHz
(MHz)
48MHz 24MHz
BSEL=1 BSEL=0
50
25
32
48 24
60
30
32
48 24
66.8 33.4
32
48 24
75.9
32
32
48 24
55
27.5
32
48 24
75.9 37.5
32
48 24
83.3 41.7
32
48 24
68.5 34.25 32
48 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.