Low-voltage operation of LMV842-Q1

Masami,

I am moving your post to this forum for better support.

Hi, Alex-san

Thank you for moving this post.

Dear, All

When the power supply of LMV842-Q1 is under 2.7V, what does operation become?
For example, although the voltage of the range in which FET operates does not satisfy the standard value of "ELECTRICAL CHARACTERISTICS", it carries out operation of Op-AMP?
Or operation of Op-AMP will not be carried out from a certain voltage? What does an output become in that case?

Thanks, Masami M.

Hello Masami,

The minimum supply voltage is chosen such that all the specifications are met at that voltage. Going lower usually means that some of these specifications will deteriorate, especially over temperature. Parts are tested in production at the minimum supply voltage (or even slightly less) to ensure they will operate.

Yes. It will still operate as an "op-amp" as the supply voltage goes below 2.7V. But everyone's definition of "operate" is different. Specifications such as GBW, Slew, Gain, CMRR and output drive are degrading. Which of these parameters are important to you determines if it is "operating".

One "clue" is to look for the Supply Voltage vs. Supply Current curve. Sometimes they will show the current below the minimum operating range. At some point there will be a "knee" where the supply current falls off. If the current is still relatively flat for the voltage you want operation down to, then it should operate well. But if you are close to, or past the knee...then operation will be poor or worse. That "knee" will move greatly over temperature. For the LMV84x, they just show the "flat" part, but it does look like it extends down close to 2.5V.

We DO NOT guarantee operation below the minimum supply voltage. There are too many "what if's".

In most cases where there is plenty of operating margin (you are not pushing any specifications too hard, or going over temperature extremes), then you may see "operation" down to at least 2V, maybe 1.8V at room temperature.

Again.."Operation" just means it is still basically functional. It will NOT meet any datasheet specs. And there is no guarantee the next batch of devices will operate the same way.

It is hard to say what the output condition will be when it starts to fail. There are too many factors to say the output will always fail the same way. But usually the output goes "high-Z" when the bias circuit fails and the output stage looses the bias current. But it may also rail hard high or low before then as the gain stages fail. So, again...no guarantee of what happens.

Regards,

I moved this to the Precision category.