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SN74CB3Q3245: With High Active

Part Number: SN74CB3Q3245

Dear  Team,

Here is Kevin from Delta Taiwan team.

Originally, customer was using TS2DDR2811 which had be EOL.

So we propose SN74CB3Q3245RGYR, but it is a low active device.

I check the portfolio, it seems we don't have high active device

Do we have high active device like TS2DDR2811 and can be directly replaced?

Or how to deal with it

BR

Kevin

  • Hi Kevin,

    You can use the SN74CB3Q3345? This device has two OE pins, 1 that is active high and 1 that is active low.

    To use this as a device with 1 active high OE pin you can connect the active low OE pin to logic high. This achieves the same results.

    I found similar post here:

    Regards

    Saminah

  • Hi Kevin,

    The SN74CB3Q3345RGYR is equivalent to the SN74CB3Q3245RGYR, except that the 3345 allows for output enable high.

    The logic scheme of the 3245 is: active low. 

    While the logic scheme of the 3345 is active low or active high. How the 3345 acheives this is that instead of a N.C. Pin it has a second Enable as shown below:

    If the OE pin is high or the ~OE pin is low the switch will turn on. This being said, only one of the enables need to be utilized and the ~OE pin can be connected to VDD to ensure only the OE pin is controlling the switch.

    This is the closest replacement we have that has an active high logic option in this configuration. 

    Best,

    Parker Dodson

  • Dear All,

    Thanks for the input.

    Just one quick question.

    If the IC don't have Vcc supply, the bus switch will be connected or disconnect?

    BR

    Kevin

  • Hi Kevin,

    This part has powered-off protection, which means when VCC = 0V, then the switch goes Hi-Z. The datasheet specs the leakage at VCC = 0V to be a max of 1uA. So the switch is essentially disconnected when VCC = 0V. 

    Best,

    Parker Dodson