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CD4067B: supply is 5V, what is the on state resistance and maximum output power

user5707026
Genius 3145 points
Part Number: CD4067B

CD4067-E2E.docxHi Engineer,

Currently my power supply is 5V.
1. What is the parameter mentioned in Figure 1, specifically, the manual is the resistance of the input signal, and what its function is.

2. The parameters mentioned in Figure 2 are the on-resistance of the channel in the on-state of the switch. According to the manual, the power supply of my system is 5V, and the on-resistance should be 15Ω. Is it correct?



3. If I want to know the maximum output current of a single channel in operation, the system power supply is 5V, how to calculate the maximum current for different input voltages, can I pass Pd=I*I*Ron, Ron is the on-resistance, Pd of a single channel How much.

4. The Pd given in Figure 3 is 500mW, which refers to the overall Pd of the chip.
What is the parameter 100mW?

  • 0
    TI__Mastermind 45420 points

    Elsa,

    What are you attempting to build with this switch?  There may be devices that more optimally fit your application.

    1) Figure one is the on-state resistance sometimes called Ron or Rdson, This is the resistance from the input pin (drain) to the output pin (source) of the FET switch.  This video will go over the on-state resistance parameter.

    1.1 TI Precision Labs - Multiplexers: On-Resistance Flatness and On-Capacitance

    2) No, Figure two shows the potential variation in the Ron parameter that could exist from channel to channel.  Figure 1 shows the on-state resistance 470 ohms with supply voltage of 5 V. 

    3) The maximum ratings table above figure 3 states the maximum DC input current, any one input +/-10mA.  Remember that this is a passive FET switch and the current passing through this switch will depend on your driver and load (which will include on-state resistance of the switch).

    4) The device power dissipation per output transistor is 100mW across full temp range which could be up to 125 deg C.  The CD4067B device is a 16:1 device which would have one output transistor connected at a time that can dissipate power across the on-state resistance.  However, the CD4097 which is also in this datasheet is a 2-channel 8:1 device which means its possible to have more than one output transistor on and dissipating power. 

    If you look at the spec immediately above for Ta= 100 to 125 deg C the power dissipation per package is 200mW which would be 100mW for each channel for the 2-channel 8:1 device.

    The 500mW spec is for lower temperature of 100 degC.  This means that if you are not operating a higher temperatures you can dissipate more power through the switch.

    Thank you,

    Adam