SY89847U

1.5GHz Precision, LVDS 1:5 Fanout with 2:1

MUX and Fail Safe Input with Internal

Termination

Precision Edge is a registered trademark of Micrel, Inc.

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

June 2007

M9999-060107-B

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

General Description

The SY89847U is a 2.5V, 1:5 LVDS fanout buffer

with a 2:1 differential input multiplexer (MUX). A

unique Fail-Safe Input (FSI) protection prevents

metastable output conditions when the selected

input clock fails to a DC voltage (voltage between

the pins of the differential input drops significantly

below 100mV).

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

internal termination architecture that can interface to

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

termination resistor networks in the signal path. The

outputs are LVDS compatible with very fast rise/fall

times guaranteed to be less than 210ps.

The SY89847U operates from a 2.5V ±5% supply

and

is

guaranteed

over

the

full

industrial

temperature

range

of

–40°C

to

+85°C.

The

SY89847U is part of Micrel’s high-speed, Precision

Edge

All support documentation can be found on Micrel’s

web site at: www.micrel.com.

Functional Block Diagram

Precision Edge

®

Features

• Selects between two sources, and provides 5

precision LVDS copies

• Fail-Safe Input

– Prevents outputs from oscillating when input is

invalid

• Guaranteed AC performance over temperature and

supply voltage:

– DC-to >1.5GHz throughput

– <1000ps Propagation Delay (IN-to-Q)

– <210ps Rise/Fall times

• Ultra-low jitter design:

• Unique, patented MUX input isolation design

minimizes adjacent channel crosstalk

• Unique, patented internal termination and VT pin

accepts DC- and AC-coupled inputs (CML, PECL,

LVDS)

• Wide input voltage range VCC to GND

• 2.5V ±5% supply voltage

• -40°C to +85°C industrial temperature range

• Available in 32-pin (5mm x 5mm) QFN package

Applications

• Fail-safe clock protection

• Ultra-low jitter LVDS clock distribution

• Rack-based Telecom/Datacom

Markets

• LAN/WAN

• Enterprise servers

• ATE

• Test and measurement