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Original question:

TS12A12511: IN Port support 3.3 V?

TS12A12511: TS12A12511 as a logic level shifter

SteeVeeDee
Intellectual 700 points
Part Number: TS12A12511
Other Parts Discussed in Thread: CD74HC4053

I'm designing a logic level shifter to take 0V < Vin < 3.3V logic and convert it to -4.5V < Vout < 0V to syncronize a switching power supply. (see SNVA807 inverting buck boost- but I want to sync it)

In other words,

IN          Vout=COM

0V           -4.5V

3.3V        0

I intend to tie V+ = 3.3V, V- = -4.5V, IN = 3.3V CMOS Logic in, NC = -4.5V, NO = 0V, and taking the output from COM.

Do you see any issues with this approach? 

I can add a little bit of resistance in series with COM if needed, but it will only be driving another CMOS input.

  • 0
    TI__Mastermind 45400 points

    SteeVeeDee,

    The voltage levels you describe are within the recommended operating conditions. You don't have to operate the TS12A12511 with symmetrical supply voltages. I was working with this part on another issue so I was actually able to set your supply voltages and confirm the switch would toggle with 3.3 V CMOS logic.

    My only concern would be to make sure that current through the switch stays within the recommended operating conditions of 50mA and you don't need a break before make feature. 
     
    Thank you,
    Adam

  • 0 in reply to Adam Torma
    Intellectual 700 points
    Thanks for the prompt response. The COM output will be driving the inputs of other IC's, so I don't see a lot of current flowing.
  • 0 in reply to Adam Torma
    Intellectual 700 points
    It appears that I will need 3 channels of level shifting, and that the CD74HC4053 configured as previously described would do the job nicely.

    In my application size is very important and it would be great if you had the '4053 in the 2.5mm x 3.5 mm package that NXP offers, 74HC4053BQ.

    If you have any other multi-channel SPDT devices in small packages to suggest, that would be helpful. Thanks!

    -Steve (a former TI'er!)
  • 0 in reply to SteeVeeDee
    TI__Mastermind 45400 points
    SteeVeeDee,

    I don't have any multi-channel 2:1 devices with dual supply rails that are < 2.5mm x 3.5 mm today. I will send this back to our product definition team.

    Thank you,
    Adam