8431AMI-21LFT

8431AMI-21LFT Datasheet

ICS8431I-21

Part	Datasheet
8431AMI-21LFT	8431AMI-21LFT (pdf)

Related Parts	Information
8431AMI-21LF	8431AMI-21LF

PDF Datasheet Preview
ICS8431I-21 350MHZ, LOW JITTER, CRYSTAL OSCILLATORTO-3.3V LVPECL FREQUENCY SYNTHESIZER The ICS8431I-21 is a general purpose clock frequency synthesizer for IA64/32 application. The VCO operates at a frequency range of 250MHz to 700MHz providing an output frequency range of 62.5MHz to 350MHz. The output frequency can be programmed using the parallel interface, M0 through M8 to the configuration logic, and the output divider control pin, DIV_SEL. Spread spectrum clocking is programmed via the control inputs SSC_CTL0 and SSC_CTL1. Programmable features of the ICS8431I-21 support four operational modes. The four modes are spread spectrum clocking SSC , non-spread spectrum clock and two test modes which are controlled by the SSC_CTL[1:0] pins. Unlike other synthesizers, the ICS8431I-21 can immediately change spread-spectrum operation without having to reset the device. In SSC mode, the output clock is modulated in order to achieve a reduction in EMI. In one of the PLL bypass test modes, the PLL is disconnected as the source to the differential output allowing an external source to be connected to the TEST_I/O pin. This is useful for in-circuit testing and allows the differential output to be driven at a lower frequency throughout the system clock tree. In the other PLL bypass mode, the oscillator divider is used as the source to both the M and the Fout divide by This is useful for characterizing the oscillator and internal dividers. • Fully integrated PLL • Differential 3.3V LVPECL output • Crystal oscillator interface • Output frequency range 62.5MHz to 350MHz • Crystal input frequency range 14MHz to 25MHz • VCO range 250MHz to 700MHz • Programmable PLL loop divider for generating a variety of output frequencies • Spread Spectrum Clocking SSC fixed at 1/2% modulation for environments requiring ultra low EMI • PLL bypass modes supporting in-circuit testing and on-chip functional block characterization • Cycle-to-cycle jitter 30ps maximum • 3.3V supply voltage • -40°C to 85°C ambient operating temperature • Replaces ICS8431I-01 • Available in both, Standard and RoHS/Lead-Free compliant packages BLOCK DIAGRAM XTAL_IN XTAL_OUT OSC ÷ 16 PLL PHASE DETECTOR ÷2 VCO M0:M8 Configuration Logic SSC Control Logic PIN ASSIGNMENT FOUT nFOUT TEST_I/O M0 1 M1 2 M2 3 M3 4 M4 5 M5 6 M6 7 M7 8 M8 9 SSC_CTL0 10 SSC_CTL1 11 VEE 12 TEST_I/O 13 VCC 14 28 nP_LOAD 27 VCC 26 XTAL_IN 25 XTAL_OUT 24 nc 23 nc 2 VCCA 21 VEE 20 MR 19 DIV_SEL 1 8 VCCO 17 FOUT 16 nFOUT 15 VEE ICS8431I-21 28-Lead SOIC 7.5mm x 18.05mm x 2.25mm package body M Package Top View 8431AMI-21 nP_LOAD SSC_CTL0 SSC_CTL1 DIV_SEL ICS8431I-21 350MHZ, LOW JITTER, CRYSTAL OSCILLATORTO-3.3V LVPECL FREQUENCY SYNTHESIZER FUNCTIONAL DESCRIPTION The ICS8431I-21 features a fully integrated PLL and therefore requires no external components for setting the loop bandwidth. The output of the oscillator is divided by 16 prior to the phase detector. With a 16MHz crystal this provides a 1MHz reference frequency. The VCO of the PLL operates over a range of 250MHz to 700MHz. The output of the M divider is also applied to the phase detector. The PLL loop divider or M divider is programmed by using inputs M0 through M8. While the nP_LOAD input is held LOW, the data present at M0:M8 is transparent to the M divider. On the LOW-to-HIGH transition of nP_LOAD, the M0:M8 data is latched into the M divider and any further changes at the M0:M8 inputs will not be seen by the M divider until the next LOW transition on nP_LOAD. The phase detector and the M divider force the VCO output frequency to be M times the reference frequency by adjusting the VCO control voltage. Note that for some values of M either too high or too low , the PLL will not achieve lock. The output of the VCO is scaled by a divider prior to being sent to the LVPECL output buffer. The divider provides a 50% output duty cycle. The programmable features of the ICS8431I-21 support four output operational modes and a programmable M divider and output divider. The four output operational modes are spread spectrum clocking SSC , non-spread spectrum clock and two test modes and are controlled by the SSC_CTL[1:0] pins. The relationship between the VCO frequency, the crystal fre- quency and the M divider is defined as follows: TABLE ORDERING INFORMATION Part/Order Number Marking Package Shipping Packaging Temperature 8431AMI-21 ICS8431AMI-21 28 Lead SOIC Tube -40°C to 85°C 8431AMI-21T ICS8431AMI-21 28 Lead SOIC 1000 tape & reel -40°C to 85°C 8431AMI-21LF ICS8431AMI-21LF 28 Lead "Lead-Free" SOIC Tube -40°C to 85°C 8431AMI-21LFT ICS8431AMI-21LF 28 Lead "Lead-Free" SOIC 1000 tape & reel -40°C to 85°C NOTE Parts that are ordered with an "LF" suffix to the part number are the Pb-Free configuration and are RoHS compliant. While the information presented herein has been checked for both accuracy and reliability, Integrated Device Technology, Inc. IDT assumes no responsibility for either its use or for 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 and industrial applications. Any other applications such as those requiring high reliability, or other extraordinary environmental requirements are not recommended without additional processing by IDT. IDT reserves the right to change any circuitry or specifications without notice. IDT does not authorize or warrant any IDT product for use in life support devices or critical medical instruments. 8431AMI-21 ICS8431I-21 350MHZ, LOW JITTER, CRYSTAL OSCILLATORTO-3.3V LVPECL FREQUENCY SYNTHESIZER 17 19 Description of Change Updated datasheet's header/footer with IDT from ICS. Ordering Information Table - removed ICS prefix from Part/Order Number column. Added lead-free marking. Added Contact Page. Date 11/22/10 8431AMI-21 ICS8431I-21 350MHZ, LOW JITTER, CRYSTAL OSCILLATORTO-3.3V LVPECL FREQUENCY SYNTHESIZER We’ve Got Your Timing Solution. 6024 Silver Creek Valley Road San Jose, CA 95138 Sales 800-345-7015 inside USA +408-284-8200 outside USA Fax 408-284-2775 Tech Support 2010 Integrated Device Technology, Inc. All rights reserved. Product specifications subject to change without notice. IDT, the IDT logo, ICS and HiPerClockS are trademarks of Integrated Device Technology, Inc. Accelerated Thinking is a service mark of Integrated Device Technology, Inc. All other brands, product names and marks are or may be trademarks or registered trademarks used to identify products or services of their respective owners. Printed in USA 8431AMI-21

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ICS8431I-21
350MHZ, LOW JITTER, CRYSTAL OSCILLATORTO-3.3V LVPECL FREQUENCY SYNTHESIZER

The ICS8431I-21 is a general purpose clock frequency synthesizer for IA64/32 application. The VCO operates at a frequency range of 250MHz to 700MHz providing an output frequency range of 62.5MHz to 350MHz. The output frequency can be programmed using the parallel interface, M0 through M8 to the configuration logic, and the output divider control pin, DIV_SEL. Spread spectrum clocking is programmed via the control inputs SSC_CTL0 and SSC_CTL1.

Programmable features of the ICS8431I-21 support four operational modes. The four modes are spread spectrum clocking SSC , non-spread spectrum clock and two test modes which are controlled by the SSC_CTL[1:0] pins. Unlike other synthesizers, the ICS8431I-21 can immediately change spread-spectrum operation without having to reset the device.

In SSC mode, the output clock is modulated in order to achieve a reduction in EMI. In one of the PLL bypass test modes, the PLL is disconnected as the source to the differential output allowing an external source to be connected to the TEST_I/O pin. This is useful for in-circuit testing and allows the differential output to be driven at a lower frequency throughout the system clock tree. In the other PLL bypass mode, the oscillator divider is used as the source to both the M and the Fout divide by This is useful for characterizing the oscillator and internal dividers.
• Fully integrated PLL
• Differential 3.3V LVPECL output
• Crystal oscillator interface
• Output frequency range 62.5MHz to 350MHz
• Crystal input frequency range 14MHz to 25MHz
• VCO range 250MHz to 700MHz
• Programmable PLL loop divider for generating a variety
of output frequencies
• Spread Spectrum Clocking SSC fixed at 1/2% modulation for environments requiring ultra low EMI
• PLL bypass modes supporting in-circuit testing and on-chip functional block characterization
• Cycle-to-cycle jitter 30ps maximum
• 3.3V supply voltage
• -40°C to 85°C ambient operating temperature
• Replaces ICS8431I-01
• Available in both, Standard and RoHS/Lead-Free
compliant packages

BLOCK DIAGRAM

XTAL_IN XTAL_OUT

OSC ÷ 16

PLL PHASE DETECTOR
÷2 VCO

M0:M8

Configuration Logic

SSC Control Logic

PIN ASSIGNMENT

FOUT nFOUT

TEST_I/O

M0 1 M1 2 M2 3 M3 4 M4 5 M5 6 M6 7 M7 8 M8 9 SSC_CTL0 10 SSC_CTL1 11 VEE 12 TEST_I/O 13 VCC 14
28 nP_LOAD 27 VCC 26 XTAL_IN 25 XTAL_OUT 24 nc 23 nc 2 VCCA 21 VEE 20 MR 19 DIV_SEL 1 8 VCCO 17 FOUT 16 nFOUT 15 VEE

ICS8431I-21
28-Lead SOIC 7.5mm x 18.05mm x 2.25mm package body

M Package Top View
8431AMI-21
nP_LOAD

SSC_CTL0 SSC_CTL1 DIV_SEL

ICS8431I-21
350MHZ, LOW JITTER, CRYSTAL OSCILLATORTO-3.3V LVPECL FREQUENCY SYNTHESIZER

FUNCTIONAL DESCRIPTION

The ICS8431I-21 features a fully integrated PLL and therefore requires no external components for setting the loop bandwidth. The output of the oscillator is divided by 16 prior to the phase detector. With a 16MHz crystal this provides a 1MHz reference frequency. The VCO of the PLL operates over a range of 250MHz to 700MHz. The output of the M divider is also applied to the phase detector.

The PLL loop divider or M divider is programmed by using inputs M0 through M8. While the nP_LOAD input is held LOW, the data present at M0:M8 is transparent to the M divider. On the LOW-to-HIGH transition of nP_LOAD, the M0:M8 data is latched into the M divider and any further changes at the M0:M8 inputs will not be seen by the M divider until the next LOW transition on nP_LOAD.

The phase detector and the M divider force the VCO output frequency to be M times the reference frequency by adjusting the VCO control voltage. Note that for some values of M either too high or too low , the PLL will not achieve lock. The output of the VCO is scaled by a divider prior to being sent to the LVPECL output buffer. The divider provides a 50% output duty cycle.

The programmable features of the ICS8431I-21 support four output operational modes and a programmable M divider and output divider. The four output operational modes are spread spectrum clocking SSC , non-spread spectrum clock and two test modes and are controlled by the SSC_CTL[1:0] pins.

The relationship between the VCO frequency, the crystal fre-
quency and the M divider is defined as follows:
TABLE ORDERING INFORMATION

Part/Order Number

Marking

Package

Shipping Packaging Temperature
8431AMI-21

ICS8431AMI-21
28 Lead SOIC

Tube
-40°C to 85°C
8431AMI-21T

ICS8431AMI-21
28 Lead SOIC
1000 tape & reel
-40°C to 85°C
8431AMI-21LF

ICS8431AMI-21LF 28 Lead "Lead-Free" SOIC

Tube
-40°C to 85°C
8431AMI-21LFT

ICS8431AMI-21LF 28 Lead "Lead-Free" SOIC
1000 tape & reel
-40°C to 85°C

NOTE Parts that are ordered with an "LF" suffix to the part number are the Pb-Free configuration and are RoHS compliant.

While the information presented herein has been checked for both accuracy and reliability, Integrated Device Technology, Inc. IDT assumes no responsibility for either its use or for 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 and industrial applications. Any other applications such as those requiring high reliability, or other extraordinary environmental requirements are not recommended without additional processing by IDT. IDT reserves the right to change any circuitry or specifications without notice. IDT does not authorize or warrant any IDT product for use in life support devices or critical medical instruments.
8431AMI-21

ICS8431I-21
350MHZ, LOW JITTER, CRYSTAL OSCILLATORTO-3.3V LVPECL FREQUENCY SYNTHESIZER
17 19

Description of Change
Updated datasheet's header/footer with IDT from ICS. Ordering Information Table - removed ICS prefix from Part/Order Number column. Added lead-free marking. Added Contact Page.

Date 11/22/10
8431AMI-21

ICS8431I-21
350MHZ, LOW JITTER, CRYSTAL OSCILLATORTO-3.3V LVPECL FREQUENCY SYNTHESIZER

We’ve Got Your Timing Solution.
6024 Silver Creek Valley Road San Jose, CA 95138

Sales 800-345-7015 inside USA +408-284-8200 outside USA Fax 408-284-2775

Tech Support
2010 Integrated Device Technology, Inc. All rights reserved. Product specifications subject to change without notice. IDT, the IDT logo, ICS and HiPerClockS are trademarks of Integrated Device Technology, Inc. Accelerated Thinking is a service mark of Integrated Device Technology, Inc. All other brands, product names and marks are or may be trademarks or registered trademarks used to identify products or services of their respective owners. Printed in USA
8431AMI-21

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 8431AMI-21LFT Datasheet file may be downloaded here without warranties.

Datasheet ID: 8431AMI-21LFT 637110