I need to read 20 analog channels using cd4051B?

Discussion in 'The Projects Forum' started by somu_desoza, Mar 10, 2011.

  1. somu_desoza

    Thread Starter New Member

    Mar 10, 2011
    Hi , In my project i need to read 20 analog channels then i need to fed to Pic micro controller ..

    To read 20 channels i am using 5 cd4051B ..then analog output of all 5 cd4051B is connected to 5 different analog pins of microcontroller ..

    The voltage i need to apply is ranges from 0 to 10V .. i have a doubt whether a cd4051 works with 10V vcc or not..

    Please share your thoughts on this.

    sowmya desoza
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    Simply get the data sheet for the device. Use "cd4051" as a search term.
  3. Audioguru

    New Member

    Dec 20, 2007
    I worked for years with a huge intercom system that multiplexed 12 channels with CD4066 analog gates. A CD4051 is similar so it can do 16 channels easily.

    A CD4051 works poorly with a Vdd of 3V and works very well when its Vdd is 9V or more.
    Look at its on-resistance with various supply voltages in its datasheet.
  4. SgtWookie


    Jul 17, 2007
    The CD4051 will work fine on 10v, but your PIC microcontroller is limited to around 5.5v maximum for Vdd. If you attempted to operate it on 10v, you would burn it up.

    The analog and digital input/output range for a PIC cannot exceed its' power rails, so you cannot directly measure a 0v-10v signal, nor can you provide the mux/demux address selects without a level translator.

    If you can reduce your input signals to a range of 0v-5v prior to the mux/demux, then you could operate both the 4051 and the PIC on 5v.