The ADG3257 is a CMOS bus switch comprised of four 2:1 multiplexers/demultiplexers with high impedance outputs. The device is manufactured on a CMOS process. This provides low power dissipation yet high switching speed and very low on resistance， allowing the inputs to be connected to the outputs without adding propagation delay or generating additional ground bounce noise.

　　The ADG3257 operates from a single 3.3 V/5 V supply. The control logic for each switch is shown in Table 1. These switches are bidirectional when on. In the off state， signal levels are blocked up to the supplies. When the power supply is off， the switches remain in the off state， isolating Port A and Port B.

　　This bus switch is suited to both switching and level translation applications. It can be used in applications requiring level trans-lation from 3.3 V to 2.5 V when powered from 3.3 V. Additionally， with a diode connected in series with 5 V VDD， the ADG3257 may also be used in applications requiring 5 V to 3.3 V level translation.