• Selects between two clocks, and provides 8 precision, low skew LVPECL output copies
• Guaranteed AC performance over temperature and supply voltage:
• <975ps in-to-out tpd
• <180ps tr/tf
• <40ps output-to-output skew
• Unique input isolation design minimizes crosstalk
• 150fs RMS phase jitter
• <0.7psRMS MUX crosstalk-induced jitter
• Unique input termination and VTpin 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
• Available in 32-pin (5mm x 5mm) QFN package

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 part of Micrel's high-speed, Precision Edge® product line.