How does this switch work

Discussion in 'Digital Circuit Design' started by ForumlaM, Dec 2, 2017.

  1. ForumlaM

    Thread Starter New Member

    Dec 2, 2017
    1
    0
    Hi

    I would like to use a switch for example the switch HMC221B (datasheet is attached) . As we can see on the attached picture.
    switch.png
    For that switch, as we can see in the datasheet, we need to add a circuit with two 74HC04. I would like to know from that circuit what is the meaning of VCTL and how do I create it ? Do we control both A and B both in same time with one input named VCTL? Do we have the control over VCTL?

    And if I put between 3V and 5V for VCTL does it mean that VCTL=high?
    If I put 0 V at VCTL, does it mean VCTL=low and cause B to be high and A to be low?
    Do I really need to use two 74HC04 in that case?

    Thank you
     
    Last edited: Dec 2, 2017
  2. Reloadron

    Distinguished Member

    Jan 15, 2015
    3,629
    1,632
    TYPICAL APPLICATION CIRCUIT Two cascaded, CMOS inverters, biased with VDD = 5 V, can generate complementary control voltages, VCTL = 0 V/5 V, for the A and B inputs. Therefore, the HMC221B can be controlled from a single CMOS input line (see Figure 15).

    Your posted circuit is Figure 15, VCTL (the control voltage) can be 0 volts for an Off state and 5 volts for an On state. Using a hex inverter like the 7404 series allows the switch to toggle. When A is High, B is Low and when B is High A is Low. Control Voltage Range (A and B) is −0.2 V dc to 12 V dc. See the control inputs on the data sheet.

    Ron
     
  3. WBahn

    Moderator

    Mar 31, 2012
    23,093
    6,946
    Are you SURE you want to use that switch? Are you really switching low-power RF signals?
     
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