SY89112U

SY89112U 2.5/3.3V Low-Jitter, Low-Skew 1:12 LVPECL Fanout Buffer with 2:1 Input MUX and Internal Termination General Description The SY89112U is a low-jitter, low-skew, high-speed LVPECL 1:12 differential fanout buffer optimized for precision telecom and enterprise server distribution applications. The input includes a 2:1 MUX for clock switchover application. Unlike other multiplexers, this input includes a unique isolation design to minimize channel-tochannel crosstalk. The SY89112U distributes clock frequencies from DC to >2GHz guaranteed over temperature and voltage. The SY89112U incorporates a synchronous output enable (EN) so that the outputs will only be enabled/disabled when they are already in the LOW state. This reduces the chance of generating “runt” clock pulses. The SY89112U differential input includes Micrel’s unique, patent-pending 3-pin input termination architecture that directly interfaces to any differential signal (AC- or DCcoupled) as small as 100mV (200mVpp) without any level shifting or termination resistor networks in the signal path. For AC-coupled input interface, an on-board output reference voltage (VREF-AC) is provided to bias the center-tap (VT) pin. The outputs are 800mV, 100Kcompatible LVPECL with fast rise/fall times guaranteed to be less than 220ps. The SY89112U 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 SY89112U is part of Micrel’s high-speed, Precision Ed...