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SY89837U

Micrel, Inc.

M9999-022007

hbwhelp@micrel.com or (408) 955-1690

DESCRIPTION

Selects between two clocks, and provides 8

precision, low skew LVPECL output copies

Guaranteed AC performance over temperature and

supply voltage:

Wide operating frequency: 1kHz to >1.5GHz

• <40ps output-to-output skew

Unique input isolation design minimizes crosstalk

Ultra-low jitter design:

Unique input termination and VT pin accepts DC- or

AC-coupled inputs (CML, PECL, LVDS)

800mV LVPECL output swing

Power supply +2.5V ±5% or +3.3V ±10%

–40°C to +85°C industrial temperature range

FEATURES

PRECISION 1:8 LVPECL FANOUT

BUFFER WITH 2:1 RUNT PULSE

ELIMINATOR INPUT MUX

SY89837U

APPLICATIONS

Redundant clock distribution

Fail-safe clock protection

Rev.: D

Amendment: /0

Issue Date: February 2007

The SY89837U is a low jitter, low skew, high-speed 1:8

fanout buffer with a unique, 2:1 differential input multiplexer

(MUX) optimized for clock redundant switchover applications.

Unlike standard multiplexers, the SY89837U unique 2:1 runt

pulse eliminator (RPE) input MUX prevents any short cycles

or “runt” pulses during switchover. In addition, a unique fail-

safe input protection prevents metastable conditions when

the selected input clock fails to a static DC differential voltage

(differential input voltage drops below 200mV). The

SY89837U distributes clock frequencies from 1kHz to

1.5GHz, guaranteed, over temperature and voltage.

The differential input includes Micrel’s unique, 3-pin input

termination architecture that allows customers to interface

to any differential signal (AC- or DC-coupled) as small as

200mV without any level shifting or termination resistor

networks in the signal path. The outputs are 800mV, 100k

compatible LVPECL with fast rise/fall times guaranteed to

be less than 200ps.

The SY89837U operates from a +2.5V ±5% or

+3.3V ±10% supply and is guaranteed over the full industrial

temperature range of –40°C to +85°C. The SY89837U is

All support documentation can be found on Micrel’s web

site at: www.micrel.com.

Precision Edge is a registered trademark of Micrel, Inc.

MicroLeadFrame and MLF are registered trademarks of Amkor Technology, Inc.