The NB4L858M is a high−bandwidth low voltage fully differential dual 2 x 2 crosspoint switch with CML outputs that is suitable for applications such as SDH/SONET DWDM and high speed switching applications. Design technique minimizes jitter accumulation,crosstalk, and signal skew which make this device ideal for loop−through and protection channel switching application. Each 2 x 2 crosspoint switch can fan out and/or multiplex up to 3Gb/s data and 3 GHz clock signals.Differential inputs incorporate a pair of internal 50 Ω termination resistors in a center−tapped configuration (VTDx Pins) and can accept LVPECL (Positive ECL) or CML input signal without any external component. This feature provides transmission line termination on−chip, at the receiver end, eliminating external components. Differential 16 mA CML output provides matching internal 50 Ω terminations, and 400 mV output swings when externally terminated, 50 Ω to VCC.The SELECT inputs are single−ended and can be driven with either LVCMOS or LVTTL input levels. The device is housed in a low profile 7 x 7 mm 32−pin LQFP package.