MK1491E-14R

MK1491E-14R Datasheet

MK1491-14 OPTi ACPI Firestar Clock Source

Part	Datasheet
MK1491E-14R	MK1491E-14R (pdf)

Related Parts	Information
MK1491E-14RTR	MK1491E-14RTR

PDF Datasheet Preview
MK1491-14 OPTi ACPI Firestar Clock Source The MK1491-14 is a low cost, low jitter, high performance clock synthesizer for OPTi’s Firestar and Firestar+ chipsets for Pentium Processor-based mobile computer applications. Using analog Phase-Locked Loop PLL techniques, the device uses a 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. • 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 VDD HOST1-4 FS1:0 Synch./Asynch. PCI STOP# SLOW# Low EMI Enable SEL0 SEL1 HOST/PCI Clocks Fixed Clock Host/2 MUX Output Buffers Output Buffers Output Buffers Output Buffer 4 HOST1:4 2 HOST 5, 7 EHOST6 5 PCI 1:5 XI MHz crystal Crystal Oscillator Output Buffer Output Buffer F2 MHz MDS 1491-14 B Integrated Circuit Systems, Inc. • 525 Race Street • San Jose •CA •95126 • 408 295-9800tel • MK1491-14 OPTi ACPI Firestar Clock Source Pin Assignment VDD 1 X14I 2 X14O 3 GND 4 14.3 HS 5 HOST1 6 HOST2 7 VDDHOST1-4 8 HOST3 9 HOST4 10 GND 11 HOST5 12 EHOST6 13 VDDHOST5-7 14 Table F1, F2 Frequency Select MHz 28 STOP# SEL1 SEL0 27 F1 SEL0 26 VDD 25 F2 PS 24 PCI FS1 1 23 GND Ordering Information Part/Order Number MK1491E-14R MK1491E-14RTR Marking MK1491E-14R MK1491E-14R Low EMI Feature Package Temperature 28 pin SSOP 0-70°C Add Tape & Reel External Components The MK1491 requires some inexpensive external components for proper operation. Decoupling capacitors of 0.1µF should be connected on each VDD pin to ground, as close to the MK1491 as possible. A series termination resistor of may be used for each clock output. See the discussion on page 4 for other external resistors required for proper I/O operation. The MHz oscillator has internal caps that provide the proper load for a parallel resonant crystal with CL=18pF. For tuning with other values of CL, the formula 2• CL-18 gives the value of each capacitor that should be connected between X1 and ground and X2 and ground. While the information presented herein has been checked for both accuracy and reliability, MicroClock Incorporated assumes no responsibility for either its use or for the infringement of any patents or other rights of third parties, which would result from its use. No other circuits, patents, or licenses are implied. This product is intended for use in normal commercial applications. Any other applications such as those requiring extended temperature range, high reliability, or other extraordinary environmental requirements are not recommended without additional processing by MicroClock. MicroClock reserves the right to change any circuitry or specifications without notice. MicroClock does not authorize or warrant any MicroClock product for use in life support devices or critical medical instruments. Pentium is a trademark of Intel Corporation MDS 1491-14 B Integrated Circuit Systems, Inc. • 525 Race Street • San Jose •CA •95126 • 408 295-9800tel •

PDF Datasheet Preview

MK1491-14 OPTi ACPI Firestar Clock Source

The MK1491-14 is a low cost, low jitter, high performance clock synthesizer for OPTi’s Firestar and Firestar+ chipsets for Pentium Processor-based mobile computer applications. Using analog Phase-Locked Loop PLL techniques, the device uses a 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.
• 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

VDD HOST1-4

FS1:0 Synch./Asynch. PCI

STOP# SLOW# Low EMI Enable

SEL0 SEL1

HOST/PCI Clocks

Fixed Clock

Host/2 MUX

Output Buffers

Output Buffers

Output Buffers

Output Buffer
4 HOST1:4
2 HOST 5, 7 EHOST6
5 PCI 1:5

XI MHz crystal

Crystal Oscillator

Output Buffer

Output Buffer

F2 MHz

MDS 1491-14 B

Integrated Circuit Systems, Inc.
• 525 Race Street
• San Jose
•CA
•95126
• 408 295-9800tel
•

MK1491-14 OPTi ACPI Firestar Clock Source

Pin Assignment

VDD 1 X14I 2 X14O 3 GND 4 14.3 HS 5 HOST1 6 HOST2 7 VDDHOST1-4 8 HOST3 9 HOST4 10 GND 11 HOST5 12 EHOST6 13 VDDHOST5-7 14

Table F1, F2 Frequency

Select MHz
28 STOP# SEL1 SEL0
27 F1 SEL0 26 VDD
25 F2 PS
24 PCI FS1 1
23 GND
Ordering Information

Part/Order Number MK1491E-14R

MK1491E-14RTR

Marking MK1491E-14R MK1491E-14R

Low EMI Feature

Package

Temperature
28 pin SSOP
0-70°C

Add Tape & Reel

External Components

The MK1491 requires some inexpensive external components for proper operation. Decoupling capacitors of 0.1µF should be connected on
each VDD pin to ground, as close to the MK1491 as possible. A series termination resistor of may be used for each clock output. See the discussion on page 4 for other external resistors required for proper I/O operation. The MHz oscillator has internal caps that provide the proper load for a parallel resonant crystal with CL=18pF. For tuning with other values of CL, the formula 2• CL-18 gives the value of each capacitor that should be connected between X1 and ground and X2 and ground.

While the information presented herein has been checked for both accuracy and reliability, MicroClock Incorporated assumes no responsibility for either its use or for the infringement of any patents or other rights of third parties, which would result from its use. No other circuits, patents, or licenses are implied. This product is intended for use in normal commercial applications. Any other applications such as those requiring extended temperature range, high reliability, or other extraordinary environmental requirements are not recommended without additional processing by MicroClock. MicroClock reserves the right to change any circuitry or specifications without notice. MicroClock does not authorize or warrant any MicroClock product for use in life support devices or critical medical instruments.

Pentium is a trademark of Intel Corporation

MDS 1491-14 B

Integrated Circuit Systems, Inc.
• 525 Race Street
• San Jose
•CA
•95126
• 408 295-9800tel
•

Notice: we do not provide any warranties that information, datasheets, application notes, circuit diagrams, or software stored on this website are up-to-date or error free. The archived MK1491E-14R Datasheet file may be downloaded here without warranties.

Datasheet ID: MK1491E-14R 637433