© 2000 California Micro Devices Corp. All rights reserved.

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215 Topaz Street, Milpitas, California 95035

Tel: (408) 263-3214

Fax: (408) 263-7846

www.calmicro.com

CALIFORNIA MICRO DEVICES

PRN299

1

POSITIVE / PSEUDO ECL (PECL) CLOCK TERMINATION NETWORK

Features

• Stable resistor network

• Reduces power dissipation on the clock lines

• Ideal for high-speed clock termination

• Reduces board space by 70% vs. 1206 discretes

and component count by more than 50%

PAC VGA200™ is a trademark of California Micro Devices Corp.

Application Note

High speed microprocessors line Intel’s Pentium/P6®, Apple PowerPC®, SPARC® and other CISC and RISC based systems need

well-controlled and precise clock signals to maintain a synchronous systems. The fast edge rated clock signals will exhibit

transmission line effects on the clock lines resulting in undershoots and overshoots. The integrated PECL termination is

designed to suppress the undershoots and overshoots on the clock lines. The PECL RC terminator dissipates very low power

compared to the resistor termination network.

Why thin.film R networks? The PECL termination is an integrated R network fabricated on a silicon substrate using

advanced thin film technology. This will have a fixed time constant and will not create additional skew on the clock lines. It

has a low parasitic inductance compared to discrete and conventional thick film R terminators and provide effective termination

at high frequencies.

Applications

• PECL clock termination

When placing an order please specify desired shipping: Tubes or Tape & Reel.

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