SN74LS240: Threshold Voltage

Shota Mago

Expert 6580 points

Part Number: SN74LS240

Hi team,

SN74LS240NS shows hysteresis on the datasheet but it doesn't specify its threshold voltage.

Could you please provide each high→low and low→high threshold voltage?

Best regards,

Shota Mago

over 4 years ago

0 Karan Kotadia over 4 years ago

TI__Genius 16725 points

Hi Shota,

The VIL or VIH are listed in the electrical characteristics section of the datasheet shown below.

Thanks!

-Karan

0 Shota Mago over 4 years ago in reply to Karan Kotadia

TI__Expert 6580 points

Hi Karan-san

Thanks for your quick reply.

In accordance to datasheet, it shows that hysteresis voltage is 0.4V(typ).

So I think there is actual threshold voltage for each Low→High/High→Low which should be VT+ − VT-−=0.4V.

Is it possible to provide the actual threshold voltage if you have?

Best regards,

Shota Mago

0 Clemens Ladisch over 4 years ago in reply to Shota Mago

Guru 243910 points

The datasheet specifies the hysteresis, but not the absolute voltage of the thresholds. They can be anywhere between V_IL and V_IH.

0 Karan Kotadia over 4 years ago in reply to Clemens Ladisch

TI__Genius 16725 points

Hi,

You should never be operating near the threshold voltages. The VIH and VIL specs I have given is what you should conform to when switching on the device. The hysteresis will help if the input signal has a slow rising or falling edge as the device will not falsely switch or oscillate at the output.

Thanks!

-Karan

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SN74LS240: Threshold Voltage