The CBTLV16292 is a single 12-bit multiplexing / demultiplexing bus switch, which provides high speed switching. This device has very low ON resistance, resulting in under 250ps propagation delay throught the switch. The demultiplexer side has a 500 resistor (R pulldown) termination to GND to eliminate floating nodes. When the select (S) input is low, the A port is connected to the B1 port, and the R pulldown is connected to the B2 port. Similarly, when the S input is high, A port is connected to B2 port and the R pulldown is connected to B1 port.