SY89464U Precision LVPECL 1:10 Fanout with 2:1 Runt Pulse Eliminator MUX and Internal Termination General Description The SY89464U is a low jitter 1:10 LVPECL fanout buffer with a 2:1 differential input multiplexer (MUX) optimized for redundant source switchover Precision Edge applications. Unlike standard multiplexers, the Features SY89464Us unique 2:1 Runt Pulse Eliminator Selects between two sources, and provides 10 (RPE) MUX prevents any short cycles or runt precision LVPECL copies pulses during switchover. In addition, a unique Fail- Guaranteed AC performance over temperature and Safe Input (FSI) protection prevents metastable output conditions when the selected input clock fails supply voltage: to a DC voltage (voltage between the pins of the Wide operating frequency: 1kHz to >1.5GHz differential input drops below 100mV). < 1100ps In-to-Out t pd The differential input includes Micrels unique, 3-pin < 220ps t /t r f internal termination architecture that allows Unique, patent-pending MUX input isolation design customers to interface to any differential signal (AC- minimizes adjacent channel crosstalk ) or DC-coupled) as small as 100mV (200mV PP Fail-Safe Input prevents oscillations without any level shifting or termination resistor Ultra-low jitter design: networks in the signal path. The outputs are 800mV, <1ps random jitter RMS 100K-compatible LVPECL with fast rise/fall times <1ps cycle-to-cycle jitter RMS guaranteed to be less than 220ps. <10ps total jitter (clock) PP The SY89464U operates from a 2.5V 5% or 3.3V <0.7ps MUX crosstalk induced jitter RMS 10% supply and is guaranteed over the full Unique patented internal termination and VT pin industrial temperature range of 40C to +85C. The accepts DC- and AC-coupled inputs (CML, PECL, SY89464U is part of Micrels high-speed, Precision LVDS) Edge product line. 800mV LVPECL output All support documentation can be found on Micrels 2.5V 5% or 3.3V 10% supply voltage web site at: www.micrel.com. Output enable -40C to +85C industrial temperature range Available in 44-pin (7mm x 7mm) QFN package Applications Redundant clock switchover Fail-safe clock protection Markets LAN/WAN Enterprise servers ATE Test and measurement United States Patent No. RE44,134 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 Micrel, Inc. SY89464U Typical Application Simplified Example Illustrating Runt Pulse Eliminator (RPE) when Primary Clock Fails December 2007 2 M9999-120607-B hbwhelp micrel.com or (408) 955-1690