The SY58021U is a 2.5V/3.3V precision, high-speed, fully differential 1:4 LVPECL fanout buffer. Optimized to provide four identical output copies with less than 15ps output skew and only 70 fsRMS phase jitter, the SY58021U can process clock signals as fast as 4GHz.The differential input includes Micrel's unique, 3-pin input termination architecture interfaces to differential LVPECL, CML, and LVDS signals (AC- or DC-coupled) as small as 100mV without any level-shifting or termination resistor networks in the signal path. For AC-coupled input interface applications, an on-board output reference voltage (VREF-AC) is provided to bias the VT pin. The outputs are 100k LVPECL compatible, with extremely fast rise/fall times guaranteed to 70fs.The SY58021U operates from a 2.5V ±5% supply or 3.3V ±10% supply and is guaranteed over the full industrial temperature range (-40°C to +85°C). For applications that require faster rise/fall times, or greater bandwidth, consider the SY58022U 1:4 fanout buffer with 400mV LVPECL output swing, or the SY58020U 1:4 CML fanout buffer. The SY58021U is part of Micrel's high-speed, Precision Edge® product line.