SY89838U Precision 1:8 LVDS Clock Fanout Buffer with 2:1 Runt Pulse Eliminator Input MUX General Description The SY89838U is a low jitter, low skew, high-speed Precision Edge 1:8 fanout buffer with a unique, 2:1 differential input Features multiplexer (MUX) optimized for redundant source switchover applications. Unlike standard multiplexers, Selects between two clocks, and provides 8 the SY89838U unique 2:1 Runt Pulse Eliminator precision, low skew LVDS output copies (RPE) MUX prevents any short cycles or runt pulses 2:1 MUX input provides a glitch-free, stable LVDS during switchover. In addition, a unique fail-safe input output protection prevents metastable conditions when the Guaranteed AC performance over temperature and selected input clock fails to a DC voltage (voltage supply voltage: between the pins of the differential input drops below Wide operating frequency: 1kHz to >1.5GHz 200mV). The SY89838U distributes clock frequencies <150ps t /t r f from 1kHz to 1.5GHz, guaranteed, over temperature <40ps output-to-output skew and voltage. Unique patent-pending input isolation design The differential input includes Micrels unique, 3-pin minimizes crosstalk input termination architecture that allows customers to Fail-safe input prevents oscillation interface to any differential signal (AC- or DC-coupled) as small as 200mV (400Mv ) without any level PP Ultra-low jitter design: shifting or termination resistor networks in the signal 150fs RMS phase jitter path. The outputs are 350mV compatible LVDS with <0.7ps MUX crosstalk induced jitter RMS fast rise/fall times guaranteed to be less than 150ps. Unique patent-pending input termination and VT pin The SY89838U operates from a 2.5V 5% supply and accepts DC- and AC-coupled inputs (CML, PECL, is guaranteed over the full industrial temperature range LVDS) of 40C to +85C. For applications that require 350mV LVDS output swing 800mV LVPECL outputs, consider the SY89837U. The Power supply 2.5V +5% SY89838U is part of Micrels high-speed, Precision 40C to +85C industrial temperature range Edge product line. Available in 32-pin (5mm x 5mm) QFN package All support documentation can be found on Micrels web site at: www.micrel.com. Applications Redundant clock switchover Failsafe clock protection Markets LAN/WAN Enterprise Servers ATE Test and Measurements United States Patent No. RE44,134 Precision Edge is a registered trademark of Micrel, Inc May 2008 M9999-051308-D hbwhelp micrel.com or (408) 955-1690 Micrel, Inc. SY89838U Typical Application May 2008 2 M9999-051308-D hbwhelp micrel.com or (408) 955-1690