The DG3157A, DG3157B are high-speed single-pole double-throw, low voltage switch. Using sub-micro CMOS technology, the DG3157A, DG3157B achieves low onresistance and negligible propagation delay. The DG3157A, DG3157B can handle both analog and digital signals and permits signals with amplitudes of up to VCC to be transmitted in either direction. Select pin of control logic input can be over the V+. When the select pin is low, B0 is connected to the output A pin. When the select pin is high, B1 is connected to the output A pin. The path that is open will have a high-impedance state with respect to the output A pin. Break before make is guaranteed. The DG3157A has an internal pull down resistor on the control pin S, while the DG3157B does not.