LMV751

Attila Roman

Other Parts Discussed in Thread: LMV751, TLV9051

Hi,

I am using LMV751 as an input buffer. Pin5 3.3V, pin 4 connected to pin1 output to an ADC, pin3 input from 0 to 3.0V, pin2 GND. When input voltage (pin3) is higher than 2.83V, the output is 3.3V suddenly. If the input voltage is 2.82V, the output is 2.823V, which is OK. From the datasheet "SNOS468E –AUGUST 1999–REVISED MARCH 2013" it seems, that the maximum input voltage is supply voltage, which in my case would be 3.3V.

over 4 years ago

0 Tim Claycomb over 4 years ago

TI__Genius 15410 points

Hi Attila,

The LMV751 does not have a common mode voltage that extends to the positive supply. The common mode voltage range is from the V- to (V+)-1.4V. So in your design the common mode voltage is from 0V to 1.9V. Please see the specification Vcm on page 2 of the datasheet. The common mode range listed on page 2 is for 2.7V supply, as you can see the max common mode voltage is 1.3V which is 1.4V from the positive supply rail.

I recommend watching out TI Precision Lab Videos on Input and Output Limitations for more information.

Thank you,

Tim Claycomb

0 Sanjeev Manandhar over 4 years ago

TI__Intellectual 775 points

Hi Attila,

I believe you are violating input common-mode range of LMV751. This is not rail to rail input amplifier. TLV9051 (5 MHz) is RRIO opamp whose output will track input closely in buffer configuration. What is your care about specs for your op amp?

Sanjeev

0 Attila Roman over 4 years ago in reply to Tim Claycomb

Prodigy 160 points

Thank you.

Attila

0 Tim Claycomb over 4 years ago in reply to Attila Roman

TI__Genius 15410 points

Hi Attila,

Glad we could help!

Thanks,

Tim Claycomb

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LMV751