This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TS12A12511: maximum power dissipation

Part Number: TS12A12511

Hi team,

I have a customer that design in TS12A12511 and want to know some information about  maximum power dissipation.

Could you provide some data or report for this?

  • The absolute maximum rating for the I/O current is 50 mA. With the worst-case on-state resistance of 12.5 Ω, this would result in 31 mW.

  • Hi Len,

    Max power disipation for the device is going to be based on max specifications. 

    Power dissipation has the following formula for a simple mux/switch: P_dis = IDD*VDD + ISS*VSS + N * (I_sw_max^2 * R_on(worst_case))

    For this device N = 1 (since there is only one channel) 

    I_sw_max (continuous current limit) = 50mA 

    Generally speaking the power dissipated from VDD and VSS are going to be very low and most power is coming from the switch current - so the supply with the largest on resistance is generally the worst

    For example for a 5V supply the max power dissipated is:

    P_dis_max = 5V * 1uA + 0V + 1*(50mA * 50mA * 12.5) = 31.255mW - with the vast majority of power dissipation in the switch channel. 

    This is realistically the largest power dissipation to expect when using the device as directed (as supply currents at specification are at a max of 1uA which is very low when you are looking at <=12V for max supply). So this is basically the  de-facto limit as if you follow the directions of the device the power dissipated shouldn't be larger than 31.255mW - this is not necessarily the limit, but the device shouldn't really be going beyond that when using device as specified.

    If you have any other questions please let me know!

    Best,

    Parker Dodson

  • Hi Parker and Clemens,

    Thanks for your help.

    Our customer have other issue as below. Please provide the maximum power dissipation that pin7 of TS12a12511?

    it drops to near -12V momentarily. (blue wave is 7pin )

  • Hi Len,

    1st - that surge is beyond -6.5V minimum on VCC by almost double which can cause damage to the device as this is well out of spec as well 

    The power dissipation relies on the channel current and positive supply as well as negative. The negative supply is dissipating |VSS * ISS| if yellow is the current at pin 7 is that value multiplied by the VSS value. so |-12 * 0.003694| would be 44.328mW - but as I mentioned before -12V is below the min abs value and this type of operation can ruin the device. 

    Best,

    Parker Dodson