The SY89842U is a low jitter CML, 2:1 differential input multiplexer (MUX) optimized for redundant source switchover applications. Unlike standard multiplexers, the SY89842U unique 2:1 Runt Pulse Eliminator (RPE) 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 DC voltage (voltage between the pins of the differential input drops below 100mV). The differential input includes Micrel's unique, 3-pin input termination architecture that allows customers to interface to any differential signal (AC- or DCcoupled) as small as 100mV (200mVPP) without any level shifting or termination resistor networks in the signal path. The output is 400mV CML with fast rise/fall times guaranteed to be less than 80ps. The SY89842U operates from a 2.5V 5% or 3.3V 10% supply and is guaranteed over the full industrial temperature range of 40C to +85C. The SY89842U is part of Micrel's high-speed, Precision Edge product line. All support documentation can be found on Micrel's web site at: www.micrel.com.