DRV8434: Logic control for M0 M1

Cherry Zhou

Part Number: DRV8434

Hi team,

Here's an issue from the customer may need your help:

The customer intends to use the 74LV244A and 74LV06 to control M0 / M1 on the DRV8434 because they need to work in 1/2, 1/4, 1/8, 1/16 stepping mode. So the 74LV244A and 74LV06 output high impedance, in this case, does the small current that output by 74LV244A and 74LV06 =will affect the DRV8434 decision and then enter the wrong step angle mode?

Could you help check this case? Thanks.

Best Regards,

Cherry

over 2 years ago

0 Wang5577 over 2 years ago

TI__Guru 56650 points

Cherry,

The M1 pin pulldown resistor is 200kohm; the pullup current is 10uA. What is the 74LV244A and 74LV06 output current in its high impedance around 2V?

Regards,
Wang Li

0 Cherry Zhou over 2 years ago in reply to Wang5577

TI__Mastermind 22235 points

Hi Wang,

Thanks for your support here.

Wang5577 said:
What is the 74LV244A and 74LV06 output current in its high impedance around 2V?

Regarding the question, high impedance leakage current may up to 5uA(the largest). Will this have some bad impact?

Cherry Zhou said:
So the 74LV244A and 74LV06 output high impedance,

Thanks and Best Regards,

Cherry

0 Wang5577 over 2 years ago in reply to Cherry Zhou

TI__Guru 56650 points

Cherry,

If the leakage sink current may up to 5uA, only 10uA-5uA current goes into the internal pull-down resistor. The M1 pin voltage could be 1V instead 2V.

Yes. 74LV244A and 74LV06 leakage current is too high to set up a high impendence input.

Regards,

Wang Li

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DRV8434: Logic control for M0 M1