SN74LVC16T245: 10.1.1 Enable Times

R.Fukunaga

Expert 2875 points

Part Number: SN74LVC16T245

Tool/software:

Hi all,

I would like to confirm about ''10.1.1'' .The usage conditions are Vcca=3.3 V, Vccb=5 V.

It is defined as below, but where are the propagation delays (DIR to A) and (DIR to B) defined?

I saw the answer in the related E2E, but I could not understand it well.

(+) SN74LVC16T245: questions about datasheet section 10.1.1 - Logic forum - Logic - TI E2E support forums

For example, if I want to know tPZH (DIR to A), can I refer to the time below?

Best Regards,

Ryusuke

10 months ago

0 Clemens Ladisch 10 months ago

Guru 322010 points

Yes; the DIR and /OE control inputs behave in the same way.

0 Joshua Salinas 10 months ago

TI__Mastermind 34820 points

Hello Ryusuke,

I agree with the response from Clemens.

Let us know if you have further questions.

Regards,

Josh

0 R.Fukunaga 10 months ago in reply to Joshua Salinas

Expert 2875 points

Hi Joshua and Clemens,

Thank you for your reply.

I understand that (DIR to *) should refer to nOE of FROM INPUT.

If the above is correct, Should I refer to the left side or the right side of the equation below?

I think the contents of the equation do not match the parameter of 7.8 Switching Characteristics: VCCA = 3.3 V ±0.3 V.

Best Regards,

Ryusuke

+1 Clemens Ladisch 10 months ago in reply to R.Fukunaga

Guru 322010 points

The test conditions are different. For section 7.8, see figure 3. The equations in section 10.1.1 are for a different case, when the signal that goes in the other direction also has a different value. For example, if the direction originally is A to B, and the input and output pins are both low, and the direction is switched, then you first have to wait for pin B to be deactivated, and then for the low B signal to be propagated to A. This case does not actually happen in practice because you would not want to have two devices driving the line at the same time.