SN74LV06A: About l Transition Rate specification

Ryoma Ohashi

Expert 5045 points

Part Number: SN74LV06A

Hi team,

My customer has a question with below app note.

SLLA364A https://www.ti.com/lit/wp/slla364a/slla364a.pdf

For LV-A series, it is specified that the transition rate is Δt/ΔV=20ns/V(Vcc=4.5V to 5.5V)

My customer wants to know the voltage range used to specify this spec.

They guess that is will be from Vcc x 0.3~Vcc x 0.7 from VIL(max) and VIH(min) with considering the shoot-through current at the input CMOS.

From the document, it seems that it is measured from 10% to 90%.

What will be the voltage range for the measurement?

Regards,

Ohashi

over 2 years ago

+1 Clemens Ladisch over 2 years ago

Guru 316690 points

This specification does not need a voltage range. The Δt/Δv value describes the slope of the edge at every point; the edge must be at least this fast at all points.

In the app note, the edges shown are straight lines. But if an edge varies in speed, then it is possible that a part of the edge is too slow (and if that part is near the switching threshold, you can get oscillations):

0 Ryoma Ohashi over 2 years ago in reply to Clemens Ladisch

TI__Expert 5045 points

Hi Clemens,

So, it means that the transition rate is measured from all of the range/ all the point. Or, in other word, it is guaranteed that the slope will be faster than this at every point, right?

Regards,

Ohashi

+1 Clemens Ladisch over 2 years ago in reply to Ryoma Ohashi

Guru 316690 points

Correct.

0 Ryoma Ohashi over 2 years ago in reply to Clemens Ladisch

TI__Expert 5045 points

Hi Clemens,

Sorry, but let me check it again.

Should the input singnal be faster than Δt/Δv in the range out of VIL(max) to VIH(min) (Vcc x 0.3~Vcc x 0.7).

Or is input signal has to be faster than Δt/Δv from 0V~Vcc to prevent the oscillation?

Regards,

Ohashi

+1 Clemens Ladisch over 2 years ago in reply to Ryoma Ohashi

Guru 316690 points

The V_IL/V_IH specifications guarantee that any input voltage lower/higher than the limit are read as logic low/high. In other words, a DC voltage at V_IL or V_IH is allowed. The Δt/Δv limit applies only to the "invalid" region between the thresholds.

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SN74LV06A: About l Transition Rate specification