General Description
The Fairchild Switch FSTU3125 provides four high-speed CMOS TTL-compatible bus switches. The low On Resistance of the switch allows inputs to be connected to outputs without adding propagation delay or generating additional ground bounce noise. The A and B Ports are protected against undershoot to support an extended range to 2.0V below ground. Fairchild’s integrated Unders hoot Hardened Circuit (UHC) senses undershoot at the I/O and responds by preventing voltage differentials from developing and turning the switch on.

Features
■ Undershoot hardened to −2V (A and B Ports)
■ 4Ω switch connection between two ports
■ Minimal propagation delay through the switch
■ Low lCC
■ Zero bounce in flow-through mode
■ Control inputs compatible with TTL level
■ See application notes AN-5008 and AN-5021 for details on undershoot