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MK1491-14 Datasheet, PDF (1/4 Pages) Integrated Circuit Systems – OPTi ACPI Firestar Clock Source | |||
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MK1491-14
OPTi ACPI Firestar Clock Source
Description
The MK1491-14 is a low cost, low jitter, high
performance clock synthesizer for OPTiâs
Firestar and Firestar+ chipsets for Pentiumâ¢
Processor-based mobile computer applications.
Using analog Phase-Locked Loop (PLL)
techniques, the device uses a 14.318 MHz
crystal input to produce multiple output
clocks up to 75 MHz. It provides selectable
Host and PCI local bus clocks as well as
selectable clocks for Super I/O or Universal
Serial Bus (USB). The device has up to seven
Host output clocks.
The chip has three different power down
modes that reduce power on various clocks.
Features
⢠Packaged in 28 pin, 150 mil wide SSOP
⢠Provides all critical timing for OPTi ACPI Firestar
and Firestar+
⢠Early Host clock of 3.5ns
⢠Separate VDD and skew adjust for Host 5,6, and 7
supports field upgrade to Firestar+ and new 2.5V
processors
⢠48MHz USB, 24MHz SIO, and Audio clock support
⢠Single pin CPU(Host) slowdown to 33.3MHz
⢠Multiple power down modes
⢠Low EMI Enable pin reduces EMI radiation (patent
pending)
Block Diagram
VDD
3
GND
4
VDD HOST5-7
HS
VDD HOST1-4
FS1:0
Synch./Asynch. PCI
STOP#
SLOW#
Low EMI Enable
PS
SEL0
SEL1
HOST/PCI
Clocks
Fixed
Clock
Host/2
MUX
33M
Output
Buffers
Output
Buffers
Output
Buffers
Output
Buffer
4
HOST1:4
2
HOST 5, 7
EHOST6
5
PCI 1:5
F1
XI
14.31818 MHz
crystal
XO
Crystal
Oscillator
Output
Buffer
Output
Buffer
F2
14.318 MHz
MDS 1491-14 B
1
Revision 061801
Integrated Circuit Systems, Inc. ⢠525 Race Street ⢠San Jose â¢CA â¢95126 ⢠(408)295-9800tel ⢠www.icst.com
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