ICS843252 データシートの表示（PDF） - Integrated Circuit Systems

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ICS843252

FEMTOCLOCKS™ CRYSTAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER

Integrated Circuit Systems 

Integrated

Circuit

Systems, Inc.

PRELIMINARY

ICS843252

FEMTOCLOCKS™CRYSTAL-TO-3.3V LVPECL

FREQUENCY SYNTHESIZER

GENERAL DESCRIPTION

The ICS843252 is a 2 differential output LVPECL

ICS

Synthesizer designed to generate Ethernet refer-

HiPerClockS™ ence clock frequencies and is a member of the

HiPerClocks™ family of high performance clock

solutions from ICS. Using a 19.53125MHz or

25MHz, 18pF parallel resonant crystal, the following frequen-

cies can be generated based on the settings of 4 frequency

select pins (SEL[A1:A0], SEL[B1:B0]): 625MHz, 312.5MHz,

156.25MHz, and 125MHz.

The two banks have their own dedicated frequency select

pins and can be independently set for the frequencies

mentioned above. The ICS843252 ICS’ 3rd generation

low phase noise VCO technology and can achieve 1ps or

lower typical rms phase jitter, easily meeting Ethernet

jitter requirements. The ICS843252 is packaged in a small

16-pin TSSOP package.

FEATURES

• Two 3.3V differential LVPECL output pairs

• Using a 19.53125MHz or 25MHz crystal, the two output

banks can be independently set for 625MHz, 312.5MHz,

156.25MHz or 125MHz

• Crystal oscillator interface

• VCO range: 490MHz to 680MHz

• RMS phase jitter @ 156.25MHz (1.875MHz - 20MHz):

0.47ps (typical)

• Full 3.3V supply mode

• 0°C to 70°C ambient operating temperature

• Industrial temperature available upon request

• Available in both standard and lead-free RoHS-compliant

packages

BLOCK DIAGRAM

SELA[0:1} Pullup

2

XTAL_IN

XTAL_OUT

OSC

Phase

Detector

VCO

490MHz - 680MHz

FB_SEL Pulldown

SELB[0:1} Pullup

2

Feedback Divider

0 = ÷25 (default)

1 = ÷32

0 0 ÷1

0 1 ÷2

1 0 ÷3

1 1 ÷4 (default)

0 0 ÷2

0 1 ÷4

1 0 ÷5

1 1 ÷8 (default)

QA

nQA

QB

nQB

PIN ASSIGNMENT

nQB 1

QB 2

VCCO_B 3

SELB1 4

SELB0 5

VCCO_A 6

QA 7

nQA 8

16 XTAL_IN

15 XTAL_OUT

14 VEE

13 SELA1

12 SELA0

11 VCC

10 VCCA

9 FB_SEL

ICS843252

16-Lead TSSOP

4.4mm x 5.0mm x 0.92mm

package body

G Package

Top View

The Preliminary Information presented herein represents a product in prototyping or pre-production. The noted characteristics are based on

initial product characterization. Integrated Circuit Systems, Incorporated (ICS) reserves the right to change any circuitry or specifications

without notice.

843252AG

www.icst.com/products/hiperclocks.html

REV. A NOVEMBER 9, 2005

1

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