SN74LV07A: Offline Support Request

user5982066

Part Number: SN74LV07A

I am using LV07 in the switch circuit.
The output pin of LV07 is used in applications where Hi-Z output and Low output are periodically repeated.
However, it may be disturbed by disturbance crosstalk at Hi-Z output.

As an example,
(1) A noise of -800mV (220us) is generated at the output pin.
(2) A noise of -800mV (5us) is generated at the output pin.

It will exceed absolute voltage -0.5V, is there a risk of destruction?

over 6 years ago

0 Emrys Maier over 6 years ago

TI__Guru* 97016 points

Hello,
What's more important than time or voltage is current. How much current is flowing through the output negative clamp diode when the voltage drops below -0.5V? The datasheet lists 50mA as the maximum clamp current. As long as you remain below that value, the device will not be damaged.

0 user5982066 over 6 years ago

Prodigy 150 points

Hello

What is the Vf of the clamp diode (V)?

I want to find it by ID (-50mA) >( 0V-(VIN + Vf)) / R.
* 1 VIN = -800mV Vf = TBD

How do you think in terms of energy?

Best regards

0 Emrys Maier over 6 years ago in reply to user5982066

TI__Guru* 97016 points

The clamp diode is not characterized as part of the datasheet. You can assume it will turn on around 0.5V, and clamp to a maximum of 0.8V until it is destroyed by excessive current. Most engineers just use Vf = 0.7V and limit the current to a very low value (ie less than 1mA). There's no good reason to choose a resistor that provides a current close to the maximum limits of the device.

Logic

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SN74LV07A: Offline Support Request