Fast SPDT analog switch?

Discussion in 'General Electronics Chat' started by autorelease, Feb 27, 2009.

  1. autorelease

    Thread Starter Active Member

    Jan 26, 2009
    I'm currently using an HI-303 SPDT analog switch, and I'm finding its propagation delay (a few hundred nanoseconds) to be too long.

    Can anyone recommend a SPDT analog switch with a switching time comparable to that of the 4066? (about 60 nanoseconds or so)

    I also had the idea to build an SPDT using two switches in a 4066: connect the outputs of the two switches together, connect the control signal to one switch and an inverted control signal to the other. (see attached schematic).

    However, since the inverter has a propagation delay (about 7 nanoseconds for the 74HC04), it's possible for switch 1 to close while switch 2 is closed, thus shorting the two inputs. One of the inputs is a +5V source and the other is a -5V source. Is it safe for the two inputs to be shorted for a few nanoseconds, or should I add a diode or something to prevent that?

    Edit: The output of the switch is going through a resistor to a TL074 op-amp.
    Last edited: Feb 27, 2009