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CD74HC190: Load Data Inputs at Power-On?

Expert 3170 points

Replies: 3

Views: 123

Part Number: CD74HC190

Hello,

For the CD74HC190, I do not plan to control LOAD with any form of MCU or switch, and would prefer to just tie it to either VCC or GND, but I would like to to load the initial value on the ABCD Data Inputs (hardwired) at power-up. Can this be done, or do I need to trigger the load after the IC has been turned on? My best guess right now is to tie LOAD to VCC when powering up. 

Best Regards,

Mitch M, TI Sensing Products Applications Support

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TI makes no warranties and assumes no liability for applications assistance or customer product design. You are fully responsible for all design decisions and engineering with regard to your products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning your designs. All information in this correspondence and in any related correspondence is provided "as is"  and is subject to TI's Important notice and disclaimer.

  • Hi Mitch,

    You can use the same circuit described in this video to do a 'load' at system startup:

    The only caveat is that your 'power on' needs to be relatively fast, and not a slow ramp -- or your RC values might have to be too large to be viable.


    Looking for a low voltage translator? Check out the AXC family that supports 0.7V to 3.3V translation!

    The Logic Minute training page has videos on many interesting topics that all are kept shorter than 5 minutes.

  • In reply to Emrys Maier:

    Thanks Emrys!

    Do you know what the default value will be if I do not load anything?

    Best Regards,

    Mitch M, TI Sensing Products Applications Support

    Getting Started with Current Sensing Video Training Series

    Hall Effect Sensor Video Training Series

    TI makes no warranties and assumes no liability for applications assistance or customer product design. You are fully responsible for all design decisions and engineering with regard to your products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning your designs. All information in this correspondence and in any related correspondence is provided "as is"  and is subject to TI's Important notice and disclaimer.

  • In reply to Mitch M:

    Hey Mitch,

    There's an FAQ on this topic here:

    Short version - this is a latched device (it uses flip-flops for the counter), so the outputs are unknown at startup. All counters will have some kind of reset or load pin because of this.


    Looking for a low voltage translator? Check out the AXC family that supports 0.7V to 3.3V translation!

    The Logic Minute training page has videos on many interesting topics that all are kept shorter than 5 minutes.

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